JP2010278142A - Thermal type element and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal type element that assure a fast thermal response of the function members and prevent deformation, by overcoming the problem that, in the thermal type element which integrates function members accompanied by heat operation function members such as a heating part and a heat sensitive part and the like are broken by expansion and contraction due to thermal expansion caused by rapid temperature change, and to provide a method of manufacturing the thermal type element. <P>SOLUTION: The thermal type element having a structure of forming a bridge of a thin layer on a cavity 30 provided in a substrate 20, includes: a function member whose size is changed with a temperature; and a size increase and decrease member 60 whose size is changed with a temperature so as to absorb the size change of the function member. The function member and the size increase and decrease member 60 are coupled and bridged on the cavity 30 provided in the substrate 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thermal element having a heat generating or heat sensitive member and a method for manufacturing the thermal element.

  In recent years, a technology of a heating element (also referred to as a micro heater) that supplies Joule heat by supplying power to a resistor serving as a heat generating portion has been disclosed (for example, Patent Document 1). For example, the atmosphere meter described in Patent Document 1 integrates a heat generating portion forming a thin thin layer cross-linked on a cavity of a Si substrate as a functional member. As described above, since the heat generating portion of the heat generating element is not in direct contact with the Si substrate, the heat loss from the heat generating portion to the Si substrate is reduced. It is formed in a minute dimension using Therefore, the thermal element can be brought to a predetermined temperature with less power. This is a so-called MEMS (Micro Electro Mechanical System), and therefore, the heat capacity of the heat generating portion is small, and power can be applied to reach a predetermined temperature in a few milliseconds.

  The heat generating portion as described above can be quickly changed from a low temperature state to a high temperature state, or from a high temperature state to a low temperature state. Therefore, when the coefficient of thermal expansion of the constituent material of the heat generating part is large, the heat generating part may be deformed by expanding and contracting at a high speed, and the heat generating part may be destroyed due to stress concentration on the portion supporting the heat generating part on the cavity.

  In addition, similar to the heat generating element, there is a heat sensitive element in which a temperature detection unit forming a thin thin layer cross-linked on the cavity of the Si substrate is integrated as a functional member. Also in the case of the thermosensitive element, since the rapid thermal response is used, the expansion and contraction as described above may occur and may be deformed.

  Here, regarding the displacement due to thermal expansion, the thermal expansion of an object having a length l that can be freely deformed is generally expressed by the following formula (1).

  Lh = Ll (1 + α (Th−Tl)) (1)

  Here, Lh: length at high temperature, Ll: length at low temperature, Th: temperature at high temperature, Tl: temperature at low temperature, and α: expansion coefficient. Further, when the above equation (1) is expressed as a displacement Lh−Ll = Δl due to thermal expansion, the following equation (2) is obtained.

  Δl = α · Ll (Th−Tl) (2)

  As apparent from the above formula (2), a displacement corresponding to the temperature difference occurs except when the physical property value α is zero.

  As described above, in the case of the heat generating element, in the structure in which the heat generating part is separated from the substrate as shown in FIG. 19, the heat generating part deforms into a convex shape due to thermal expansion, and stress concentration on the part that supports the heat generating element This causes a problem that the heat generating part is destroyed.

  Here, FIG. 19 shows a schematic configuration example of a thermal element related to the present invention. In the thermal element shown in FIG. 19, the resistor 10 is formed of a material having a positive coefficient of thermal expansion such as Pt, Au, NiCr, and the resistor 10 is bridged on the cavity 30 provided in the substrate 20. And it is used as a functional member. Both ends of the resistor 10 are connected to the electrode portions 40 on the substrate, respectively. In such a resistor 10, the portion on the substrate cannot be expanded and contracted because it is constrained by the substrate 20, but the portion on the cavity is not constrained by the substrate 20 and can be expanded and contracted. Accordingly, in the resistor whose dimensions change depending on the temperature state, the resistor is flat in the low temperature state as shown in FIG. 19C, but in the high temperature state, the resistor is caused by thermal expansion as shown in FIG. 19B. 10 was extended in the center direction and a large deflection had occurred.

  In order to solve the above problems, in a thermal sensor having a diaphragm structure in which a heating resistance and a thermal resistance are sandwiched between a support film and a protection film, the tensile stress of the support film or the protection film is set to 50 MPa or more and 250 MPa or less with respect to the base material. Thus, a technique for suppressing deformation of the heat generating portion is disclosed (for example, Patent Document 2).

Further, as another technique for solving the above problem, in the floating membrane formed on the Si substrate and having a peripheral portion made of SiO ₂ , the membrane central portion made of the SiO ₂ film is used to cancel the stress inside the membrane. also disclosed technology to replace the Si ₂ N ₄ (e.g., Patent Document 3).

  Further, as a technique for compensating for stress, a technique for a stress compensation coating is disclosed (for example, Patent Document 4). Specifically, in the technique described in Patent Document 3, a film having a negative thermal expansion coefficient is used to compensate for the warp of the warped structure formed by a film process for forming a film on a substrate at a high temperature. Further, it is formed on the concave surface of the warped structure, that is, on the film formed by the above-described coating process at a temperature higher than the use temperature. Thereby, the substrate can have a relatively flat structure.

  Furthermore, as a technique related to the above problem, a technique of a sample holding device incorporated in an apparatus that performs X-ray diffraction measurement while changing the sample temperature is disclosed (for example, Patent Document 5). Specifically, in the technique described in Patent Document 5, the displacement in the vertical direction due to the temperature change of the sample placement portion having a positive thermal expansion coefficient is the displacement of the first support member and the second support member having different thermal expansion coefficients. Is suppressed.

  However, in the techniques described in Patent Document 2 and Patent Document 3, since the stress depends on the temperature, pressure, thickness, and the like at the time of manufacture, there is a problem that adjustment is complicated and variation becomes large. It was. For this reason, it is difficult for the techniques described in Patent Document 2 and Patent Document 3 to make the stress balance constant.

  In the technique described in Patent Document 4, the film deposited on the substrate surface has a problem that the film is peeled off because the stress acting on the interface of the film becomes larger at the end portion where the warpage is larger. Usually, the difference in stress is reduced to prevent film peeling.

  As described above, the technique described in Patent Document 5 suppresses the vertical displacement due to the temperature change of the sample placement portion having a positive thermal expansion coefficient by the displacement of the first support member and the second support member having different thermal expansion coefficients. Technology. In other words, the technique described in Patent Document 5 does not suppress the displacement in the plane direction, and unlike the thermal element, the sample placement portion is not of a configuration in which the sample placement portion is placed in a cavity provided in the substrate. Furthermore, there has been a problem that the time element is not taken into consideration for the suppression of the displacement of the sample placement portion.

  The present invention has been made in view of such a situation, and in a thermal element in which functional members having thermal action are integrated, a heat generating part, a heat sensitive part, and the like due to expansion and contraction due to thermal expansion caused by a rapid temperature change. It is an object of the present invention to provide a thermal element that solves the problem of breakage of a functional member, prevents deformation while ensuring rapid thermal response of the functional member, and a method for manufacturing the thermal element.

  The thermal element of the present invention is a thermal element having a structure in which a thin layer is bridged on a cavity provided in a substrate, and a functional member whose dimensions change with temperature and a change in the dimensions of the functional member are absorbed. And a dimension increasing / decreasing member whose dimension changes with temperature, wherein the functional member and the dimension increasing / decreasing member are connected and bridged on a cavity provided in the substrate.

  The method for manufacturing a thermal element according to the present invention includes a functional member forming step for forming a functional member whose dimensions change with temperature on a substrate, and a dimension according to temperature so as to absorb a change in the dimensions of the functional member on the substrate. The dimension increasing / decreasing member forming step is formed by connecting the dimension increasing / decreasing member changing with the functional member, and the cavity forming step for forming the cavity in the substrate so that the functional member and the dimension increasing / decreasing member are connected and bridged on the cavity. And.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to prevent a deformation | transformation of a functional member, ensuring the quick thermal responsiveness of a thermal-type element.

It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 1) It is a figure which shows the example of the temperature distribution of the thermal type element which concerns on this embodiment. It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 2) It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 3) It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 4) It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 5) It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 6) It is a schematic diagram which shows a mode when electric power is applied to the heat generating element which concerns on this embodiment. It is a figure which shows the structural example of the dimension increase / decrease member of the thermal type element which concerns on this embodiment. It is a figure which shows the structural example of the functional member of the thermal type element which concerns on this embodiment. It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 7) It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 8) It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 9) It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 10) It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 10) It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. (Embodiment 11) It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. Embodiment 12 It is a figure which shows the schematic structural example of the thermal type element which concerns on this embodiment. Embodiment 12 It is a figure which shows the schematic structural example of the thermal type element relevant to this invention.

  Hereinafter, examples of embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1A shows a schematic configuration example of the thermal element according to the present embodiment. 1B and 1C are cross-sectional views taken along the line Ia-Ib in FIG. 1A, and FIG. 1D is an example of a connecting portion between the resistor of the functional member and the dimension increasing / decreasing member. Show. FIG. 1B shows an example in which the thermal element is in a high temperature state, and FIG. 1C shows an example in which the thermal element is in a low temperature state. Moreover, the arrow shown in the figure represents expansion and contraction due to thermal expansion.

  In the thermal element according to the present embodiment, the resistor 10 serving as a functional member cross-linked on the cavity 30 provided in the substrate 20 is connected and supported by the dimension increasing / decreasing member 60.

  First, a method for manufacturing a thermal element according to this embodiment will be described.

First, in order to maintain insulation between the electrodes, an insulating film such as SiO ₂ , Ta ₂ O ₅ , Si ₃ N ₄ or the like is formed on the surface of the substrate 20 by sputtering or the like, for example. In this embodiment, an example in which a Si substrate is applied as a substrate is shown, but the present invention is not limited to this. Thereafter, a resistive film having a positive thermal expansion coefficient, such as Pt, Au, NiCr, W, or the like having high electrical conductivity, which becomes the resistor 10, is formed on the insulating film by, for example, 0.3 μm by sputtering.

  Next, in order to process the resistive film into the shape of the resistor, a folded pattern having a width of 4 μm, a longitudinal direction of 170 μm, and a lateral direction of 2 μm is formed using a photoresist, and the resistive film is etched using the folded pattern as a mask. Thereafter, the resist is removed to produce a resistor having a predetermined shape. At this time, the resistors on the final cavity are arranged so that the length thereof is 154 μm.

In order to form the dimension increasing / decreasing member 60, an opening pattern of 10 μm × 200 μm is formed with a photoresist at a position overlapping with the short direction of the resistor 10, and a material having a negative thermal expansion coefficient on the surface, for example, ZrW ₂ O ₈ (Zirconium tungstate), HfW ₂ O ₈ (hafnium tungstate), Li ₂ O—Al ₂ O ₃ —nSiO ₂ (lithium aluminum silicate), Mn ₃ CuN—Mn ₃ GeN (manganese nitride), etc. For example, a 0.3 μm film is formed, and the dimension increasing / decreasing member 60 is manufactured by removing the resist. The bridging length L of the dimension increasing / decreasing member 60 is determined according to the material used and the temperature.

If it is necessary to use a non-insulating material and maintain the insulation between the resistor 10 and the dimension increasing / decreasing member 60, SiO ₂ , Ta ₂ O ₅ , Si ₃ N before the dimension increasing / decreasing member 60 is formed. An insulating film such as ₄ is formed.

Here, a case where the material used for the resistor 10 is Pt (α is about 9 μ / ° C.) and the material used for the dimension increasing / decreasing member 60 is ZrW ₂ O ₈ (α is about −9 μ / ° C.) is taken as an example. Thus, the cross-linking length L of the dimension increasing / decreasing member 60 is calculated. When the thermal element is used from 0 ° C. to 500 ° C., Δl is calculated by substituting Ll = 154 μm into the above equation (2), where Δl is the size of Pt that expands at a temperature difference between 0 ° C. and 500 ° C. About 0.7 μm. When the crosslinking length of ZrW ₂ O ₈ necessary for causing the same shrinkage as Δl is calculated from the above equation (2), 154 μm is obtained. Thus, L is small when the dimension increasing / decreasing member 60 is selected to be larger than α of the resistor 10, and conversely, L can be increased when a small one is selected.

Next, in order to maintain the insulation between the electrodes, a _{SiO 2, Ta 2 O 5,} Si 3 N 4 or the like of the insulating film by a sputtering method on the substrate surface, for example, 0.5μm deposited. Then, a 304 μm × 304 μm window for forming the cavity 30 by etching the Si substrate under the resistor and an opening pattern for removing the insulating film on the electrode part are formed with a photoresist, and the insulating film is formed from the opening part. Etch. Thereafter, the resist is removed.

  Subsequently, in order to form the cavity 30, the Si substrate is anisotropically etched using KOH, TMAH (tetramethylammonium hydroxide), etc., and the resistor 10 having a length of 154 μm on the cavity and the cavity 30 are formed. The dimension increasing / decreasing member 60 having a length of 154 μm, and the portion where the two are connected completes a thermal element having a size of 4 μm. The cavity 30 here is formed from the substrate surface on the side where the functional member is disposed, and is provided to insulate the functional member and the substrate from space and to reduce the heat capacity of the functional member. Since it suffices, the cavity may be formed from a substrate surface on which no functional member is arranged, a shape such as a groove, or a through hole. Furthermore, the connection part of the resistor 10 and the dimension increase / decrease member 60 is not limited to the said length, It can change suitably.

  By heating the resistor of the functional member of the thermal type element manufactured as described above to 500 ° C., for example, the power required to transfer heat to the ambient atmosphere gas and the known thermal conductivity of the ambient atmosphere Therefore, the thermal conductivity of the surrounding atmosphere can be detected at high speed. Furthermore, the gas state of the surrounding atmosphere can be detected at high speed based on the relationship between the detected thermal conductivity and the known state of the surrounding atmosphere.

  The thermal element utilizes the relationship between the thermal conductivity of the gas and the concentration of the ambient atmosphere. For example, it can be applied as a humidity sensor from the relationship between the thermal conductivity of the ambient atmosphere and the water vapor concentration in the air. it can. Furthermore, it can be applied as a hydrogen concentration sensor of a fuel cell due to the relationship between the thermal conductivity of the ambient atmosphere and the concentration of water vapor and hydrogen.

  Moreover, it can also apply to a gas sensor by coat | covering gas sensitive materials, such as a catalyst and a metal oxide semiconductor, and activating a gas sensitive material with a heat generating member. Furthermore, it can also be applied as a pressure sensor according to the relationship between the electric power required to transfer heat to the gas in the ambient atmosphere and the pressure in the known ambient atmosphere. Moreover, it can also be applied as a flow sensor according to the relationship with the flow velocity of a known ambient atmosphere.

  On the other hand, when the resistor 10 of this functional member has a resistance value corresponding to the temperature of the atmosphere, the temperature of the ambient atmosphere gas is detected at a high speed from the relationship between the known temperature and the measured resistance value, Depending on the relationship between the temperature and the state of the known ambient atmosphere, the state of the gas in the ambient atmosphere can be detected at high speed. For example, it can be applied as a flow sensor from the temperature transferred from the heat generating part of the ambient atmosphere and the relationship between the temperature and the known flow velocity. Moreover, it can apply as an acceleration sensor from the relationship between the temperature which transfers heat from the heat generating part in a sealed atmosphere, and the temperature and a known acceleration. Furthermore, it can be applied as an infrared sensor from the temperature change accompanying light absorption from the ambient atmosphere and the relationship between the temperature and known infrared rays. In addition, although it demonstrated that the thermal type element which concerns on this embodiment was applicable as said some sensor, the above-mentioned sensor is an example and is not limited to this.

  Next, absorption of expansion and contraction accompanying temperature change in the thermal element according to the present embodiment will be described.

  As shown in FIG. 1, the resistor 10 of the thermal element according to the present embodiment has one end connected to the electrode part 40 on the substrate 20 and extends from the connection part with the electrode part 40 onto the cavity 30. It is formed so as to be folded at the folded portion. The resistor 10 is connected to the dimension increasing / decreasing member 60 having a negative thermal expansion coefficient at the folded portion. Here, since the resistor 10 and the dimension increasing / decreasing member 60 on the cavity 30 can be expanded and contracted without being constrained by the substrate 20, they expand and contract in accordance with the temperature state. Therefore, as shown in FIG. 1B, the resistor 10 having a positive thermal expansion coefficient expands by Δl toward the resistance pattern front end side of the resistor 10 at a high temperature, and has a dimensional increase / decrease having a negative thermal expansion coefficient. The member 60 is displaced by Δl toward the substrate side. Therefore, the extension of the resistor 10 is absorbed by the dimension increasing / decreasing member 60, and even when the thermal element is in a high temperature state, the shape without deflection is maintained as in the low temperature state shown in FIG.

  Next, the connection between the resistor 10 and the dimension increasing / decreasing member 60 will be described.

  (D) of FIG. 1 has shown the connection part of the resistor 10 and the dimension increase / decrease member 60. FIG. The dimension increasing / decreasing member 60 laminated on the resistance pattern of the resistor 10 is not shown. Each part of the resistor 10 is defined as R1 and R2 in the longitudinal direction of the pattern and R3 in the lateral direction, and the elongation of each part from the low temperature to the high temperature is denoted as Δl1, Δl2, and Δl3, respectively. Here, since the pattern lateral direction is sufficiently smaller than the longitudinal direction, Δl3 can be ignored. Since Δl1 and Δl2 have the same size and direction and are parallel, the expansion of the entire resistor can be expressed by a displacement vector d10 having the same size and direction as Δl1. Similarly, the contraction in the longitudinal direction of the dimension increasing / decreasing member 60 can be expressed by a displacement vector d11 of Δ14. By matching the vector d10 and the vector d11, the expansion and contraction of the resistor 10 due to thermal expansion is absorbed.

  When the dimension increasing / decreasing member 60 is connected so as to face the expansion / contraction direction of the resistor 10 as in the thermal element shown in FIG. 1, and the displacement vector of the resistor 10 and the displacement vector of the dimension increasing / decreasing member 60 are matched. The arrangement is such that the expansion and contraction of the resistor 10 can be absorbed by the minimum dimension increasing / decreasing member 60.

  Next, the thermal conductivity between the resistor 10 and the dimension increasing / decreasing member 60 will be described.

  FIG. 2 shows the temperature distribution in the Ia-Ib direction of FIG. 1A when the temperature rises when the thermal conductivity of the dimension increasing / decreasing member 60 is smaller than the thermal conductivity of the resistor 10. It is. One of the conditions for determining the cross-linking length of the dimension increasing / decreasing member 60 that absorbs the expansion and contraction of the resistor 10 is the temperature, and a predetermined amount so as to match the amount of displacement of the resistor 10 in the operating temperature range depending on the material used. Crosslink length is determined. This cross-linking length is a condition in which the resistor and the dimension increasing / decreasing member are uniform and have the same temperature change. Although the absolute value of the coefficient of thermal expansion of the material used for the dimension increasing / decreasing member is often smaller than that of the material used as the resistor, the material of the dimension increasing / decreasing member also has a higher thermal conductivity than the material of the conductive resistor. Is often smaller. Due to the difference in thermal conductivity of this material, when the temperature state changes, a temperature difference is generated between the resistor bridged on the cavity and the dimension increasing / decreasing member.

  In the example shown in FIG. 2, since the thermal conductivity of the resistor is larger than the thermal conductivity of the dimension increasing / decreasing member, the heat transfer to the substrate is larger on the resistor side and the temperature on the resistor side is higher. In this state, the extension of the resistor is larger, and the extension of the resistor and the shrinkage of the dimension increasing / decreasing member are unbalanced. Therefore, even in such a case, in order to absorb the elongation of the resistor, the cross-linking length of the dimension increasing / decreasing member is made longer than a predetermined value according to the thermal conductivity so that the displacement on the dimension increasing / decreasing member side is increased. Good.

  According to the present embodiment, by providing a means for absorbing the amount of expansion and contraction of the functional member, it is difficult to be deformed even with respect to a temperature change, and stable characteristics can be obtained. In addition, by performing reliable absorption of the expansion and contraction in synchronization with the thermal response speed of the functional member, it is possible to perform a quick thermal response with minimal addition of heat capacity.

(Embodiment 2)
FIG. 3 shows a schematic configuration example of the thermal element according to the present embodiment. The difference from the configuration of the thermal element of the first embodiment is a connecting portion between the resistor 10 and the dimension increasing / decreasing member 60. In this embodiment, an example will be described in which the resistor 10 having a positive thermal expansion coefficient and the dimension increasing / decreasing member 60 having a negative thermal expansion coefficient are stacked and connected and supported between different planes. FIG. 3A is a diagram in which the lower surface of the resistor 10 and the upper surface of the dimension increasing / decreasing member 60 are connected. On the other hand, (b) of FIG. 3 connects the upper surface of the resistor 10 and the lower surface of the dimension increasing / decreasing member 60. The arrows shown in the figure represent expansion and contraction due to thermal expansion.

  In both cases in which the resistor 10 and the dimension increasing / decreasing member 60 are stacked and connected, the resistor 10 extends to the distal end side of the resistor 10 protruding from the substrate side in a high temperature state, and the dimension increasing / decreasing member 60 contracts to the substrate side. Therefore, the expansion and contraction of the resistor 10 can be absorbed by the dimension increasing / decreasing member 60. Moreover, the strength of the connecting portion can be obtained by increasing the joint area between the resistor 10 and the dimension increasing / decreasing member 60 in this manner.

  According to the present embodiment, it is possible to improve the strength of the connecting portion between the functional member and the means for absorbing the amount of expansion and contraction of the functional member, and it is possible to obtain more stable characteristics.

(Embodiment 3)
FIG. 4 shows a schematic configuration example of the thermal element according to the present embodiment. This embodiment is different from the first embodiment in that a resistor having a positive thermal expansion coefficient which is a functional member bridged on a cavity provided in the substrate 20 via a connecting member 70, and a negative thermal expansion coefficient. It is a point which connects the dimension increasing / decreasing member 60 which has these. The arrows shown in the figure represent expansion and contraction due to thermal expansion. 4A shows an example in which the connection member 70 is arranged between the resistor 10 and the dimension increasing / decreasing member 60 in the thickness direction. On the other hand, FIG. 4B shows an example in which the connecting member 70 is arranged between the resistor 10 and the dimension increasing / decreasing member 60 in the plane direction.

  This embodiment is suitable when it is necessary to insulate between the resistor 10 having a positive thermal expansion coefficient and the dimension increasing / decreasing member 60 having a negative thermal expansion coefficient, or when increasing the joining force of the connecting portion. In the thermal type element composed of the conductive resistor 10 having a positive thermal expansion coefficient and the conductive dimension increasing / decreasing member 60 having a negative thermal expansion coefficient and a large thermal conductivity, an insulating material having a small thermal conductivity is used. Since the heat transfer from the dimension increasing / decreasing member 60 to the substrate 20 can be increased as compared with the case of the dimension increasing / decreasing member 60, the temperature difference between the resistor side and the dimension increasing / decreasing member side can be reduced. Therefore, it is not necessary to consider that the unbalance of expansion and contraction between the resistor side and the dimension increasing / decreasing member side generated in the temperature distribution is the same.

  Since the expansion and contraction of the connecting member 70 connected to the resistor 10 is treated as one member whose size changes depending on the temperature together with the expansion and contraction of the resistor 10, the expansion and contraction of the connecting member 70 is absorbed by the dimension increasing / decreasing member 60. The connecting member 70 may have any positive, negative, or zero thermal expansion coefficient. Therefore, a material that strongly bonds the resistor 10 and the dimension increasing / decreasing member 60 can be selected.

  According to the present embodiment, by connecting and supporting the functional member and the dimension increasing / decreasing member via the connecting member to which the material having such a close thermal conductivity value and a small temperature distribution is applied, stable heat can be obtained. A mold element can be obtained. In addition, when connecting the dimension increasing / decreasing member and the functional member, if the joining force of the material of the dimension increasing / decreasing member is small, the connection part is disconnected especially when the size increasing / decreasing member or the functional member becomes finer due to the manufacturing process or expansion / contraction. There was a problem that made it easier to do. However, it is possible to obtain structural strength by selecting a material having a bonding force for the dimension increasing / decreasing member and the resistor as the connecting member, or by increasing the bonding area.

  Further, by connecting the functional member and the dimension increasing / decreasing member via the contact member, it is possible to combine various materials and realize various thermal elements. And since it connects via a connection member, it becomes possible to support a functional member and a dimension increase / decrease member firmly, it becomes difficult to deform | transform with respect to a temperature change, and it becomes possible to acquire the stable characteristic.

(Embodiment 4)
FIG. 5 is a diagram illustrating a schematic configuration example of the thermal element according to the present embodiment. The present embodiment is different from the first embodiment in that a plurality of resistors and electrode portions 40 are provided. FIG. 5A is a plan view showing a schematic configuration example of the thermal element according to the present embodiment. FIG. 5B is a cross-sectional view taken along the line Va-Vb in FIG. FIG. 5C shows an example of a connecting portion between the resistor and the dimension increasing / decreasing member 60. In FIG. 5C, the dimension increasing / decreasing member 60 laminated on the resistance pattern of the resistor is not shown. Moreover, the arrow in a figure represents the expansion-contraction by thermal expansion.

  As shown in FIG. 5, the thermal element according to the present embodiment has a dimension increasing / decreasing member at a position where the resistor 11 serving as a functional member bridged on the cavity provided in the insulating substrate 21 faces the expansion / contraction direction of the resistor. The dimension increasing / decreasing member 60 is connected to and supported by the other resistors 12 and 13.

  The absorption of expansion and contraction accompanying the temperature change in the thermal element according to the present embodiment will be described.

  In the present embodiment, the resistors 11 to 13 having a positive coefficient of thermal expansion bridged on the cavity provided in the insulating substrate 21 can be expanded and contracted at a portion on the cavity. Extend to the side. Moreover, the dimension increasing / decreasing member 60 having a negative thermal expansion coefficient connecting the resistors 11 to 13 contracts in the pattern longitudinal direction. Here, since the elongation in the short direction of the resistance pattern is sufficiently smaller than that in the longitudinal direction, it can be ignored.

  The expansion of the resistors 11 to 13 when changing from the low temperature state to the high temperature state is referred to as displacement vectors d10, d20, and d30, respectively. On the other hand, the contraction of the dimension increasing / decreasing member 60 facing the resistor 11 is d11, the contraction facing the resistor 12 is d21, and the contraction facing the resistor 13 is d31. To absorb the expansion and contraction of the resistor. The size increasing / decreasing member 60 that connects the resistors in the cavity has a smaller temperature distribution than the case where one end is supported by the insulating substrate 21, so that the entire expansion and contraction can be increased.

  According to the present embodiment, a stable thermal element is realized by absorbing the thermal expansion of the functional member by using a dimension increasing / decreasing member having a thermal expansion coefficient having a polarity different from that of the functional member in a portion for connecting and supporting the functional member. It becomes possible to do. In addition, it is possible to perform a quick thermal response by connecting and disposing the dimension increasing / decreasing members facing the expansion / contraction direction of the functional member to minimize the addition of heat capacity.

(Embodiment 5)
FIG. 6 is a diagram illustrating a schematic configuration example of the thermal element according to the present embodiment. As shown in FIG. 6, the present embodiment is different from the fourth embodiment in that an infrared absorption unit is provided on the cavity 30. FIG. 6A is a plan view illustrating a schematic configuration example of the thermal element according to the present embodiment. FIG. 6B is a cross-sectional view taken along the line VIa-VIb of FIG. Since the infrared absorption section absorbs infrared rays and changes its temperature, the temperature change can be detected by a thermocouple.

  The thermocouple 91 cross-linked on the cavity has a thermocouple pattern 911 made of an alumel thin film and a thermocouple pattern 912 made of a chromel thin film, and heat at a location where the thermocouple pattern 911 and the thermocouple pattern 912 are joined. The electromotive force is detected as a voltage between the electrode portions installed on the substrate connected to the thermocouple. The portion where the thermocouple pattern 911 and the thermocouple pattern 912 are joined to each other and the infrared absorbing portion 80 are connected via a dimension increasing / decreasing member 60, and the temperature in the infrared absorbing portion 80 is mediated by the dimension increasing / decreasing member 60. Heat transfer.

  The infrared absorption unit 80 absorbs heat radiated from a facing object by laminating a thin film such as platinum black on the surface. Further, instead of the Joule heating mechanism of the resistor, a Peltier element can be configured as the heating element.

  That is, in FIG. 6, the infrared absorbing portion 80 is replaced with an Al electrode, the thermocouple pattern 911 is replaced with an N-type semiconductor pattern, and the thermocouple pattern 912 is replaced with a P-type semiconductor pattern. A thin film formed by diffusing impurities in polysilicon, bridged on a cavity of a substrate, wherein at least a pair of an N-type semiconductor and a P-type semiconductor pattern are joined by an Al electrode on the cavity, and an electrode at an end of the P-type semiconductor pattern Is applied to the electrode at the end of the N-type semiconductor pattern to heat the Al electrode portion. On the other hand, if a current in the reverse direction is applied, the Al electrode portion is cooled, and thus can be controlled to an arbitrary temperature by adjusting the direction of the current and the current value. Thereby, the aggregation temperature is detected by cooling the Al electrode part on the cavity until the gas in the surrounding atmosphere is aggregated, and the dew point temperature sensor can be used to detect the dew point temperature of the atmosphere.

  According to the present embodiment, it is possible to apply a thermal element as various types of sensors.

(Embodiment 6)
FIG. 7 is a diagram illustrating a schematic configuration example of the thermal element according to the present embodiment. FIG. 7A is a plan view showing a schematic configuration example of the thermal element according to the present embodiment, and FIG. 7B is a cross-sectional view of VIIa-VIIb in FIG. . The arrows in the figure represent expansion and contraction due to thermal expansion.

  In the thermal element according to the present embodiment, the resistor 10 serving as a functional member bridged on the cavity provided in the substrate 20 is connected and supported by a plurality of dimension increasing / decreasing members 60 at positions facing the expansion / contraction direction. The resistor 10 of the thermal element according to the present embodiment is configured to fold back a plurality of resistance patterns in order to increase the resistance value and improve sensitivity, and each folded portion of the resistance pattern is connected and supported by a dimension increasing / decreasing member 60. ing.

  The absorption of expansion and contraction accompanying the temperature change in the thermal element according to the present embodiment will be described.

  The resistor 10 having a positive thermal expansion coefficient bridged on a cavity provided in the substrate 20 extends in the longitudinal direction of the resistance pattern when the resistor 10 is changed from a low temperature state to a high temperature state. Here, since the elongation in the short direction of the resistance pattern is sufficiently smaller than that in the longitudinal direction, it can be ignored. On the other hand, the dimension increasing / decreasing member 60 having a negative coefficient of thermal expansion for connecting and supporting the resistor 10 contracts in the pattern longitudinal direction when it reaches a high temperature. In each connecting portion, the expansion and contraction of the resistor can be absorbed by matching the displacement of the resistance pattern and the dimension increasing / decreasing member.

  Next, a state when power is applied to the resistor 10 of the heating element according to the present embodiment will be described.

  FIG. 8 is a schematic diagram showing a state in which power is applied to the resistor 10 of the heating element according to the present embodiment to generate heat. (A) of FIG. 8 shows an example of the time change of the temperature distribution in the VIIc-VIId direction of (a) of FIG. FIG. 8B shows an example of the temporal change in the heat generation temperature at point D in FIG. FIG. 8C shows an example of the change over time of the displacement at point D in FIG.

  As shown in FIG. 8A, the temperature distribution when the resistor 10 of the heat generating element according to the present embodiment generates heat is such that the heat from the adjacent resistance pattern is superimposed and the center where the point A exists is present. The temperature in the resistance pattern is the highest, and the temperature decreases from the resistance pattern toward the outermost resistance pattern where the point C exists. Since the expansion / contraction amount of the resistor 10 varies from pattern to pattern depending on the temperature distribution, it is necessary to match the displacement of the resistance pattern and the dimension increasing / decreasing member 60.

  Here, in this embodiment, since each pattern folding | turning part of the resistor 10 is connectedly arranged by the dimension increase / decrease member 60, as shown to FIG.9 and FIG.10, as shown in FIG. By changing the resistance pattern length R, the expansion and contraction of the resistance pattern can be absorbed more easily.

  In FIG. 9, the cross-linking length L1 of the dimension increasing / decreasing member in the peripheral part of the resistance pattern with a small expansion / contraction compared with the resistor pattern of the central part with a large expansion / contraction in the high temperature state is shown by using the temperature distribution. In this example, the length of the cross-link is made shorter than the cross-linking length L2, and the expansion and contraction at each connecting portion is matched. Further, in FIG. 10, the length R1 of the resistance pattern that is low in temperature compared to the central portion of the resistor that is high in temperature is set to be longer than the length R2 of the resistance pattern in the center, and the expansion and contraction at each connecting portion is performed. Shows an example of matching.

  Further, in the configuration in which a plurality of resistance patterns are folded and each folded portion of the resistance pattern is connected and supported by the dimension increasing / decreasing member 60 as in the resistor 10 of the present embodiment, both ends of the resistance pattern are supported by the dimension increasing / decreasing member 60. It becomes a shape, and the expansion and contraction amount of the resistance pattern is dispersed. Therefore, since the amount of expansion / contraction of the resistor 10 absorbed by one dimension increasing / decreasing member 60 is reduced, the absorption of expansion / contraction is facilitated.

  Here, as shown in FIG. 8B, time is required until the exothermic temperature is balanced. When the heat generation start time is t0, the temperature at point D is T0, the heat generation temperature equilibration time is t3, and the temperature at that time is T3, the temperature changes from T0 to T3 every moment. Therefore, the resistor 10 is connected to the dimension increasing / decreasing member 60 on the cavity that is thermally insulated in the space with small thermal conductivity, and the size increasing / decreasing member 60 causes the same temperature change as the resistor 10 due to heat transfer from the resistor 10. Can be generated. As shown in FIG. 9, by changing the bridge length of the dimension increasing / decreasing member 60 at each part to increase the heat transfer from the resistor 10 and changing the temperature distribution, the resistor as shown in FIG. 10 and the displacement of the dimension increasing / decreasing member 60.

  That is, the absolute value of the amount of expansion of the resistor 10 and the amount of contraction of the dimension increasing / decreasing member 60 at time t1, and the amount of expansion of the resistor 10 and the absolute value of the amount of contraction of the size increasing / decreasing member 60 at times t2 and t3 are combined. By using the dimension increasing / decreasing member 60 that is displaced in synchronization with the body 10, the expansion and contraction of the resistor 10 can be absorbed.

  For example, the material of the resistor 10 is Pt, the thickness is 0.3 μm, the pattern length is 100 μm, and the pattern width is 4 μm. By intermittently applying Joule heat by applying a current for 5 milliseconds, a period of 100 Hz is intermittent. If the resistor is periodically heated between 0 ° C. and 500 ° C. under the conditions, it is assumed that expansion and contraction in the pattern longitudinal direction occurs about 0.5 μm at a cycle of 100 Hz. When such expansion and contraction is repeated, the physical property value such as the resistance value of the resistor 10 changes, the predetermined heat generation temperature cannot be maintained, the characteristics of the detection element change, and brittle fatigue expands after 10,000 hours. However, it can lead to cracks. However, cracks can be prevented by using the dimension increasing / decreasing member 60 having a negative coefficient of thermal expansion at the portion for connecting and supporting the resistance pattern and absorbing the expansion and contraction.

  According to the present embodiment, by connecting the functional members with a plurality of dimension increasing / decreasing members, the functional members can be firmly supported by the surface shape, and the stability can be improved. Furthermore, by changing the cross-linking length of the dimension increasing / decreasing member and the length of the functional member according to the temperature distribution of the functional member, and absorbing the expansion / contraction of the functional member by the dimension increasing / decreasing member, a stable thermal element can be obtained. It becomes possible.

(Embodiment 7)
FIG. 11 shows a schematic configuration example of the thermal element according to the present embodiment. 11A is a plan view illustrating a schematic configuration example of the thermal element according to the present embodiment, and FIG. 11B is a cross-sectional view taken along line XIa-XIb in FIG. . The arrows in the figure represent expansion and contraction due to thermal expansion. As shown in FIG. 11, the thermal element of the present embodiment has a plurality of dimensions in a position where the resistor 14 and the resistor 15 that are cross-linked on the cavity provided in the substrate 20 are opposed to each other in the expansion / contraction direction. It is connected and supported by an increase / decrease member.

  The absorption of expansion and contraction accompanying the temperature change in the thermal element according to the present embodiment will be described.

  Resistors 14 and 15 having a positive thermal expansion coefficient bridged on a cavity provided in the substrate 20 cannot expand and contract in a portion on the substrate, but can be expanded and contracted because they are not restrained by the substrate 20 in a portion on the cavity. For this reason, in a high temperature state, it extends to the tip side with the folded portion. Further, the dimension increasing / decreasing members 61 and 62 having a negative thermal expansion coefficient connected and supported between the resistor 14 and the resistor 15 contract in the pattern longitudinal direction. Here, since the elongation in the short direction of the resistance pattern is sufficiently smaller than that in the longitudinal direction, it can be ignored.

  When the transition from the low temperature state to the high temperature state occurs, the expansion of the resistor 14 and the resistor 15 is Δl14 and Δl15, respectively, and the contraction of the dimension increasing / decreasing member 61 on the side in contact with the resistor 14 is Δl614 and the side in contact with the resistor 15 , The shrinkage of the dimension increasing / decreasing member 62 on the side in contact with the resistor 14 is Δl624, and the contraction on the side in contact with the resistor 15 is Δl625. The expansion and contraction of the portion where the resistor and the dimension increasing / decreasing member are connected, that is, Δl14 and Δl624, Δl15 and Δl625 can be matched to absorb the elongation of the resistance pattern.

  According to the present embodiment, a stable thermal element is realized by absorbing the thermal expansion of the functional member by using a dimension increasing / decreasing member having a thermal expansion coefficient having a polarity different from that of the functional member in a portion for connecting and supporting the functional member. It becomes possible to do. Further, by connecting and supporting the functional member with a plurality of dimension increasing / decreasing members, it is possible to provide a surface-shaped support, excellent strength, and a stable thermal element. Furthermore, it is possible to perform a quick thermal response by connecting and disposing the dimension increasing / decreasing members opposite to the expansion / contraction direction of the functional member to minimize the addition of heat capacity. In the thermal element according to the present embodiment, since the functional member is connected and supported by a plurality of dimension increasing / decreasing members, the functional member can be widely supported on the surface, and resistance to torsion and vibration of the functional member can be improved.

(Embodiment 8)
FIG. 12 shows a schematic configuration example of the thermal element according to the present embodiment. 12A is a plan view illustrating a schematic configuration example of the thermal element according to the present embodiment, and FIG. 12B is a cross-sectional view taken along line XIIa-XIIb in FIG. . FIG. 12C shows an example of a connecting portion between the resistor 10 of the thermal element and the dimension increasing / decreasing member 60 according to this embodiment. In FIG. 12C, the dimension increasing / decreasing member 60 laminated on the resistance pattern is not shown. The arrows in the figure represent expansion and contraction due to thermal expansion. FIG. 12 shows an example in which the resistor 10 serving as a functional member bridged on a cavity provided in the substrate 20 is connected by a plurality of dimension increasing / decreasing members 60.

  The absorption of expansion and contraction accompanying the temperature change in the thermal element according to the present embodiment will be described.

  Since the resistor 10 having a positive coefficient of thermal expansion bridged on the cavity provided in the substrate 20 can expand and contract on the cavity, the resistor 10 extends to the tip side with the folded portion in a high temperature state. Can be expressed by a vector of d10. Here, since the elongation in the short direction of the resistance pattern is sufficiently smaller than that in the longitudinal direction, it can be ignored.

  On the other hand, the dimension increasing / decreasing member 60 having a negative thermal expansion coefficient for connecting and supporting the resistor 10 in the present embodiment is not in a direction facing the resistor 10, so that the angle of the two dimension increasing / decreasing members 60 is an angle θ. It is provided at an angle. The end not connected to the resistor 10 is connected to the substrate 20. In the present embodiment, an example in which two dimension increasing / decreasing members 60 are provided will be described. However, the present invention is not limited to this.

  Assuming that one shrinkage of the dimension increasing / decreasing member is Δl61 and the other is Δl62, the contraction by the dimension increasing / decreasing member can be expressed by a vector d11 obtained by synthesizing each contraction. By matching, the expansion and contraction of the resistor can be absorbed.

  By changing the angle θ which is an angle formed by the dimension increasing / decreasing member 60 and the bridge length, and by causing the displacement vector of the dimension increasing / decreasing member 60 to correspond to the displacement vector of the resistor 10, the expansion / contraction absorption range is expanded. The present invention can also be applied to the case where the cross-linking length of the dimension increasing / decreasing member is not sufficiently obtained at the position facing the expansion / contraction direction. Moreover, even if the thermal expansion coefficient or length is not strict, it can be handled.

  According to the present embodiment, a stable thermal element is realized by absorbing the thermal expansion of the functional member by using a dimension increasing / decreasing member having a thermal expansion coefficient having a polarity different from that of the functional member in a portion for connecting and supporting the functional member. It becomes possible to do. Further, by connecting and supporting the functional member with a plurality of dimension increasing / decreasing members, it is possible to obtain a stable thermal element with excellent support strength in the surface direction. Furthermore, by changing the angle formed by the dimension increasing / decreasing member for connecting and supporting the functional member and the cross-linking length, the absorption range of expansion / contraction is expanded, and the cross-linking length of the dimension increasing / decreasing member is sufficient at a position facing the expansion / contraction direction of the functional member. It is possible to apply even when it is not obtained. It is also possible to cope with cases where the thermal expansion coefficient and length are not strict.

(Embodiment 9)
FIG. 13 shows a schematic configuration example of the thermal element according to the present embodiment. 13A is a plan view showing a schematic configuration example of the thermal element according to the present embodiment, and FIG. 13B is a cross-sectional view taken along line XIIa-XIIb in FIG. . FIG. 13C shows an example of a part of the connecting portion between the resistor of the thermal element according to the present embodiment and the dimension increasing / decreasing member. In FIG. 13C, the dimension increasing / decreasing member laminated on the resistance pattern is not shown. The arrows in the figure represent expansion and contraction due to thermal expansion. In FIG. 13, resistors 16, 17, 18, and 19 that are functional members cross-linked on the cavity provided in the substrate 20 are connected and arranged by a plurality of dimension increasing / decreasing members at an angle that does not oppose the expansion / contraction direction of the resistor, The example in which the dimension increasing / decreasing member is also connected to another resistor is shown.

  The absorption of expansion and contraction accompanying the temperature change in the thermal element according to the present embodiment will be described.

  Elongation in the high temperature state of the resistors 16, 17, 18, 19 having a positive thermal expansion coefficient bridged on the cavity provided in the substrate 20 is Δl16, Δl17, Δl18, Δl19, respectively, and negative in the high temperature state. The shrinkage of the dimension increasing / decreasing member 63 having the thermal expansion coefficient is Δl636 on the side in contact with the resistor 16 and Δl637 on the side in contact with the resistor 17. Similarly, the contraction of the dimension increasing / decreasing member 64 is also Δl647 and Δl648, the contraction of the dimension increasing / decreasing member 65 is Δl658, Δl659, and the contraction of the dimension increasing / decreasing member 66 is also Δl669, Δl666. In the resistor 16, the vector d11 obtained by synthesizing the shrinkage Δl636 and Δl666 of the dimension increasing / decreasing member connected to the resistor 16 and the extension vector d10 of the resistor 16 are matched to absorb the expansion and contraction of the resistor 16. Similarly, the expansion and contraction of each resistor can be absorbed by matching the expansion vectors d20, d30, and d40 of each resistor with the contraction vectors d21, d31, and d41.

  In the shape in which the resistor is connected and arranged by a plurality of dimension increasing / decreasing members on the cavity, the infrared absorber 80 is easily arranged on the cavity as in the fifth embodiment, and the resistor is replaced with a thermocouple to form an infrared sensor. You can also.

  According to this embodiment, since the functional member is connected and supported by a plurality of dimension increasing / decreasing members, it is possible to support a wide range of surfaces and realize a thermal element that is resistant to torsion and vibration of the resistor.

(Embodiment 10)
FIG. 14 shows a schematic configuration example of the thermal element according to the present embodiment. FIG. 14A is a plan view showing a schematic configuration example of the thermal element according to the present embodiment, and FIG. 14B is a cross-sectional view taken along line XIVa-XIVb in FIG. . FIG. 14C shows an example of a part of the connecting portion between the resistor 10 of the thermal element and the dimension increasing / decreasing member according to the present embodiment. In FIG. 14C, the dimension increasing / decreasing member laminated on the resistance pattern is not shown. The arrows in the figure represent expansion and contraction due to thermal expansion. FIG. 14 shows an example in which a resistor 10 that is a functional member bridged on a cavity provided in the substrate 20 is connected to a plurality of dimension increasing / decreasing members at an angle that does not oppose the expansion / contraction direction of the resistor 10. .

  The absorption of expansion and contraction accompanying the temperature change in the thermal element according to the present embodiment will be described.

  The resistance pattern portions projecting from the electrode portion side on the substrate of the resistor 10 having a positive thermal expansion coefficient bridged on the cavity are respectively R1 and R2, and the extension of the respective patterns in the high temperature state is Δl1 and Δl2. . Further, a resistance pattern portion connecting R1 and R2 is R3, and elongations toward the R1 side and the R2 side are Δl31 and Δl32, respectively. Further, the shrinkage of the size increasing / decreasing members 67 and 68 having a negative coefficient of thermal expansion is represented by Δl67 and Δl68. The size increasing / decreasing members are connected to the contact points of the resistance patterns R1 and R3 and the contact points of the resistance patterns R2 and R3, respectively. As shown in FIG. 14C, at the connecting portion between the resistance pattern and the dimension increasing / decreasing member, for example, a vector d10 obtained by combining the extension Δl2 of the resistance pattern R2 and the extension Δl32 of R3 and the vector d11 of the dimension increasing / decreasing member 68 By arranging so as to match, the extension of the resistance pattern can be absorbed.

  Here, in the resistor according to the present embodiment, since the force in the pattern longitudinal direction of the resistor pattern R3 also acts on the resistor patterns R1 and R2 in a high temperature state, when the expansion and contraction of the resistor pattern R3 increases, the pattern protruding portion from the substrate Is deformed. Therefore, as shown in FIG. 15, the deformation can be alleviated by connecting and supporting a dimension increasing / decreasing member between the resistance patterns R <b> 1 and R <b> 2 to disperse and absorb the extension.

  According to this embodiment, since the functional member is connected and supported by a plurality of dimension increasing / decreasing members, it is possible to realize a thermal element that can be widely supported on the surface and has excellent strength.

(Embodiment 11)
FIG. 16 shows a schematic configuration example of the thermal element according to the present embodiment. The arrows in the figure represent expansion and contraction due to thermal expansion. FIG. 16 shows an example in which a resistor 10 that is a functional member bridged on a cavity provided in the substrate 20 is connected to and supported by a plurality of dimension increasing / decreasing members at an angle that does not oppose the expansion / contraction direction of the resistor 10. .

  The absorption of expansion and contraction accompanying the temperature change in the thermal element according to the present embodiment will be described.

  The circular resistor 10 having a positive thermal expansion coefficient cross-linked on the cavity provided in the substrate 20 can be expanded and contracted on the cavity, and in a high temperature state, to the tip side protruding from the electrode portion 40 on the substrate. Elongate. The dimension increasing / decreasing member 60 having a negative coefficient of thermal expansion is connected at a plurality of locations at angles not facing the expansion / contraction direction of the resistor 10, and the end not connected to the resistor 10 is connected to the substrate. The dimension increasing / decreasing members 60 connected at a plurality of locations at angles not facing the expansion / contraction direction of the resistor 10 absorb the expansion of the resistor 10 and disperse and absorb the entire expansion / contraction. In the present embodiment, an example is shown in which the cross-linking length of the dimension increasing / decreasing member is sequentially increased as L1, L2, and L3 to absorb the expansion and contraction toward the distal end side where the expansion and contraction increases according to the temperature distribution.

  According to the present embodiment, since the functional member is connected and supported by a plurality of dimension increasing / decreasing members, the functional member is supported on the surface, and is not easily deformed even with respect to a temperature change, and the strength can be improved. In addition, it is possible to realize a stable thermal element by absorbing a thermal expansion of the functional member by using a dimension increasing / decreasing member having a coefficient of thermal expansion different from that of the functional member in a portion for connecting and supporting the functional member. It becomes possible.

  It is also possible to combine the above embodiments. For example, as the arrangement of the dimension increasing / decreasing member, a combination of an arrangement facing the expansion / contraction direction of the resistor and an arrangement at an angle not opposing the expansion / contraction direction of the resistor, and connecting and supporting the resistor and the plurality of dimension increasing / decreasing members, the heat capacity It is also possible to make the thermal element excellent in supporting strength by minimizing the addition of.

Embodiment 12
FIG. 17 shows a schematic configuration example of the thermal element according to the present embodiment. FIG. 17A is a plan view showing a schematic configuration example of the thermal element according to the present embodiment, and FIG. 17B is a cross-sectional view taken along line XVIIa-XVIIb in FIG. . The arrows in the figure represent expansion and contraction due to thermal expansion. In FIG. 17, a dimension increasing / decreasing member 60 is connected to a functional member composed of a plurality of material layers, in which a resistor 10 bridged on a cavity provided in a substrate 20 is covered with an insulating film 50, facing the expansion / contraction direction. An example is shown.

  The absorption of expansion and contraction accompanying the temperature change in the thermal element according to the present embodiment will be described.

  Since the resistor 10 having a positive thermal expansion coefficient bridged on the cavity provided in the substrate 20 and the functional member having the resistor 10 sandwiched between the insulating films 50 can be expanded and contracted on the cavity, In the state, Δl extends toward the tip of the heat generating or heat sensitive member having the folded portion of the resistor 10. Since the dimension increasing / decreasing member 60 having a negative coefficient of thermal expansion contracts to the substrate side, the contraction of the portion where the resistor 10 and the dimension increasing / decreasing member 60 are connected is made to coincide with the extension, thereby being constituted by a plurality of material layers. The expansion and contraction of the functional member to be performed can be absorbed.

  In addition, as shown in FIG. 18, even if the dimension increasing / decreasing member 60 is connected to and supported by the insulating film 50, the expansion and contraction of the functional member can be absorbed.

  Here, when the functional member is composed of a single material layer, the material layer expands and contracts in accordance with the thermal expansion coefficient of the material, and it is necessary to provide connection support corresponding to the thermal expansion coefficient of the material. On the other hand, when the functional member is composed of a plurality of material layers, unlike the case of a single material layer, due to the difference in properties depending on the temperature of each material layer, not only expansion and contraction but also warping and bending. Twist will occur. In addition, in a single material layer, it is necessary to devise a technique for reducing the residual stress depending on manufacturing conditions such as film forming speed and temperature and film thickness at the time of film formation, and there are limitations on film forming conditions or shapes. On the other hand, with multiple material layers, the thermal expansion coefficient of the material does not differ greatly, and the production conditions such as film formation speed and temperature during film formation and the film thickness are adjusted to maintain a delicate balance of residual stress. Further ingenuity is required, and there are limitations on the types of materials, film forming conditions, and shapes. In the present embodiment, since the functional member is connected and supported by the dimension increasing / decreasing member, even when the functional member is constituted by a plurality of material layers, warping or twisting due to a constituent material generated due to temperature change or its manufacturing conditions, etc. Can also be prevented.

  According to the present embodiment, by using a dimension increasing / decreasing member having a coefficient of thermal expansion different from that of the functional member in a portion for connecting and supporting the functional member, and absorbing the thermal expansion of the functional member, a stable thermal element can be realized. Become. In addition, more various combinations of materials and production conditions with a wider control range can be applied, and a wide variety of thermal elements can be realized.

  Although specifically described based on the preferred embodiments, the present invention is not limited to the above-described thermal element and the method for manufacturing the thermal element, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The thermal element according to the present invention can be used as a heating element or a thermal element. As a heat generating element, it can apply to the micro heater used, for example, in order to heat the catalyst of a gas sensor, or a metal oxide semiconductor at high speed. In addition, combinatorial microdevice microheaters for chemical synthesis of minute quantities, microchips in bio and medical fields, microheaters incorporated for PCR operations that give thermal cycles to DNA, etc. The present invention can also be applied as a micro heater incorporated in a reactor. Further, as a heat generation mechanism other than the Joule heat generation, a micro Peltier mechanism for controlling the temperature of the heat generating portion is integrated, and can be applied as a dew point sensor by generating heat or cooling.

  On the other hand, as a thermal element, for example, a temperature sensor of the atmosphere, a thermal flow sensor using the relationship between the fluid flow velocity and the heat conduction, a gas pressure sensor using the relationship between the gas density and the heat conduction, and the acceleration received by the atmosphere The present invention can be applied to an acceleration sensor using heat transfer, a gas sensor using the thermal conductivity of gas, and the like. Also applicable to infrared sensors such as thermocouples (thermopiles) that directly detect temperature rises due to light absorption, pyroelectric elements that detect changes in electrical polarization, and bolometers that detect temperature rises as resistance changes can do. Furthermore, in a gas or liquid component analyzer, these heat generating elements and heat sensitive elements can be used in combination.

DESCRIPTION OF SYMBOLS 10 Resistor 20 Board | substrate 21 Insulation board | substrate 30 Cavity 40 Electrode part 50 Insulating film 60 Size increase / decrease member 70 Connection member 80 Infrared absorption part 91 Thermocouple 92 Thermocouple 93 Thermocouple 911 Thermocouple pattern 912 Thermocouple pattern

Japanese Patent No. 2889909 Japanese Patent No. 4127697 Japanese Patent Laid-Open No. 08-264844 JP 2006-281766 A Japanese Patent No. 3717342

Claims (14)

A thermal element having a structure in which a thin layer is bridged on a cavity provided in a substrate,
Functional members whose dimensions change with temperature,
A dimension increasing / decreasing member whose dimension changes with temperature so as to absorb the change in dimension of the functional member,
The thermal element, wherein the functional member and the dimension increasing / decreasing member are connected and bridged on a cavity provided in the substrate.   2. The thermal element according to claim 1, wherein at least one of the dimension increasing / decreasing members is connected to the functional member so as to face the expansion / contraction direction of the functional member.   3. The thermal element according to claim 1, wherein at least one of the dimension increasing / decreasing members is connected to the functional member at an angle other than facing the expansion / contraction direction of the functional member.   4. The thermal element according to claim 1, wherein the dimension increasing / decreasing member has a dimension and a connecting position determined based on a temperature distribution of the functional member. 5. A connecting member;
5. The thermal element according to claim 1, wherein the functional member and the dimension increasing / decreasing member are connected and bridged on a cavity provided in the substrate via the connection member. 6. . The functional member has a positive coefficient of thermal expansion;
6. The thermal element according to claim 1, wherein the dimension increasing / decreasing member has a negative coefficient of thermal expansion.   The thermal element according to any one of claims 1 to 6, wherein the functional member includes at least one material layer.   The thermal element according to any one of claims 1 to 7, wherein the functional member includes at least one of a heat generating unit and a cooling unit.   The thermal element according to any one of claims 1 to 8, wherein the functional member includes heat detection means for detecting heat. A functional member forming step for forming a functional member whose dimensions change with temperature on the substrate;
On the substrate, a dimension increasing / decreasing member forming step of forming a dimension increasing / decreasing member whose dimension varies with temperature so as to absorb a change in the dimension of the functional member, connected to the functional member,
And a cavity forming step for forming a cavity in the substrate so that the functional member and the dimension increasing / decreasing member are connected and bridged on the cavity.   11. The method of manufacturing a thermal element according to claim 10, wherein in the dimension increasing / decreasing member forming step, at least one or more dimension increasing / decreasing members are formed so as to face each other in the expansion / contraction direction of the functional member.   The manufacturing of the thermal element according to claim 10 or 11, wherein the dimension increasing / decreasing member forming step forms at least one or more dimension increasing / decreasing members at an angle other than facing the expansion / contraction direction of the functional member. Method.   13. The dimension increasing / decreasing member forming step determines a dimension of the dimension increasing / decreasing member and a connection position with the functional member based on a temperature distribution of the functional member. The manufacturing method of the thermal type element as described in any one of. A connection member forming step of forming a connection member;
The method for manufacturing a thermal element according to claim 10, wherein the connecting member connects the functional member and the dimension increasing / decreasing member.

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