JP6560116B2 - RTD - Google Patents

Description

  The present invention relates to a temperature measuring body in which an internal resistance wiring is provided inside an insulating base made of a ceramic sintered body.

  Multilayer wiring that uses resistance wiring inside the insulating substrate as a sensor for temperature detection in high-temperature fluids such as exhaust gas (for example, several hundred to 1,000 degrees Celsius), and uses changes in the resistance of the resistance wiring due to temperature Substrates are known. As a metal material constituting the resistance wiring, platinum (Pt) or a material containing platinum as a main component is used from the viewpoint of oxidation resistance at a high temperature.

  As a component constituting a temperature detecting sensor element (hereinafter referred to as “temperature measuring element”) containing the metal material, for example, platinum is formed between a plurality of insulating layers made of a ceramic sintered body or the like and stacked on each other. A laminate of a plurality of wiring boards provided with a linear conductor made of a metallized layer or a thin film layer is known.

  Further, the electrical connection between the temperature measuring element and the control means such as the temperature monitoring and recording system is made through leads connected to electrodes arranged on the main surface of the insulating base. In addition, the connection part of these electrodes and leads is covered with a covering member made of a glass material or the like in order to reinforce the connection and prevent peeling (disconnection) due to heat or the like.

JP-A-8-201113 JP-A-11-121214

  By the way, in the step of manufacturing the temperature measuring element, the glass material of the reinforcing covering member as described above is supplied so as to cover the entire end portion of the electrode and the lead, and is solidified by baking (sintering) or the like. Is done. At that time, in the process of cooling the temperature measuring product, there are cases where the glass covering member is cracked or the lead is lifted (separated) from the electrode.

  In addition, these defects can be easily removed by inspection etc. if they are in a range that can be found visually, but fine ones are difficult to find. The cracks, cracks, and the like are enlarged by repeated heating and cooling, which may lead to a decrease in detection accuracy and a disconnection of the sensor.

  As a result of examining the above problems, the present inventor has found that the occurrence of cracks or the like in the glass covering member as described above occurs during heating and cooling of the temperature measuring element, and thermal expansion and contraction between the covering member and other members. The present invention was completed by ascertaining that it was caused by the difference in rate.

In other words, the temperature measuring element according to one aspect of the present invention is provided on an insulating base in which a plurality of insulating layers are laminated, an internal resistance wiring provided inside the insulating base, and a main surface of the insulating base. Covering an electrode, a via conductor that penetrates the insulating base in the thickness direction and electrically connects the internal resistance wiring and the electrode, a lead connected to the electrode, and an electrode side end of the electrode and the lead And a first covering member made of a glass material, and the first covering member has a thermal expansion coefficient larger than that of the lead.

The “thermal expansion coefficient” in the present invention refers to a solid “linear expansion coefficient” (also referred to as a linear expansion coefficient) obtained by applying JIS R 1618 “Method for measuring thermal expansion by thermomechanical analysis of fine ceramics”. ), And the magnitude was compared with the value of “linear expansion coefficient” (unit: 1 / K (K ⁻¹ )) in the final form of the member, not the raw material.

  Since the temperature sensing element according to one aspect of the present invention has the above-described configuration, a first covering member made of a glass material that covers the electrode side ends of the electrode and the lead is manufactured and cooled during manufacturing. In this case, the first covering member is free from cracks and vibrations, and the lead can be maintained firmly fixed to the electrode. For this reason, the performance of each product can be stabilized and the product yield can be improved.

  In addition, even when receiving heat or the like continuously during use, the connection and fixing between the electrode and the lead can be stably and reliably maintained over a long period of time. Therefore, it is possible to provide a temperature sensor with high reliability and a long lifetime.

(A) is a perspective view which shows the temperature sensing element of the 1st Embodiment of this invention, (b) is a disassembled perspective view of (a). (A) is a perspective view which shows the temperature sensing element of the 2nd Embodiment of this invention, (b) is a disassembled perspective view of (a).

  A temperature sensor according to an embodiment of the present invention will be described with reference to the accompanying drawings. The distinction between the upper and lower sides in the following description is for convenience, and does not limit the upper and lower sides when a wiring board or the like is actually used.

  1A and 1B are views showing a temperature sensing element 10 according to a first embodiment of the present invention, in which FIG. 1A is a perspective view and FIG. 1B is an exploded perspective view of FIG.

  As shown in FIG. 1B, an insulating base 1 is formed by laminating an uppermost insulating layer 1a and a plurality of insulating layers 1b (five layers in the example of FIG. 1). A lead 3 connected to a control means (not shown) is connected to the electrode 2 arranged on the main surface (upper surface in the example of FIG. 1) of the insulating substrate 1. A covering member (first member) for protecting and reinforcing the connection between the electrode 2 and the lead 3 is provided above the electrodes 2 and the ends of the connected leads 3 (two in the example of FIG. 1). 1 is provided to form a temperature measuring body 10.

  The insulating base 1 is formed by laminating flat (layered) insulating layers 1a and 1b such as a square plate, and each of the insulating layers 1a and 1b is made of, for example, an aluminum oxide sintered body or aluminum nitride. It is formed of a ceramic sintered body such as a sintered body, a mullite sintered body, or a glass ceramic sintered body.

  Inside the insulating substrate 1 and on the upper surface of each lower insulating layer 1b, an internal resistance wiring 5 having a meandering pattern, for example, is provided. The internal resistance wirings 5 of these insulating layers 1b are connected by via conductors 6 (so-called through conductors) formed in the thickness direction of the insulating base 1.

  The via conductor 6 is formed of, for example, a conductor material (metal material) whose main component is the same metal material (platinum or the like) as that of the internal resistance wiring 5, and penetrates the insulating base 1 in the vertical direction, and the upper side thereof. Is exposed on the upper surface (main surface) of the uppermost insulating layer 1 a of the insulating substrate 1.

  The electrode 2 is provided on the upper end surface (top 6a) of the via conductor 6 exposed on the upper surface of the insulating base 1, and has the same metal material (platinum or the like) as that of the internal resistance wiring 5 as a main component. A metal material is used to form a square shape, a circular shape, or the like.

The lead 3 connected to the electrode 2 is made of a metal material containing platinum, for example, like the internal resistance wiring 5, and may be made of pure platinum. The connection (joining) of the lead 3 to the electrode 2 is performed by joining means such as resistance welding or a brazing method using a brazing material containing gold. In addition, when the lead 3 is an alloy containing platinum, a typical thermal expansion coefficient (linear expansion coefficient) is 8.8 × 10 ⁻⁶ / K.

  In addition, the temperature sensing element 10 according to the first embodiment of the present invention covers the connection (joining) portion between the electrode 2 and the lead 3 on the main surface of the insulating base 1 and is a first for protecting a connection portion. The covering member 4 is provided.

  The first covering member 4 is formed of a glass material such as barium silicate glass or borosilicate glass, and can be manufactured by the following method.

  First, a slurry prepared by adding and mixing an appropriate organic binder and a solvent to raw powders such as barium silicate glass and borosilicate glass is applied on the connecting portion between the electrode 2 and the lead 3 using a dispenser or the like. In addition, an excessive supply is made in a mountain shape that completely covers these. Next, the insulating substrate 1 containing the slurry is fired at a high temperature (about 800 to 1200 ° C.) and cooled to room temperature (cooled), thereby producing the first covering member 4 that completely covers the connecting portion. .

Here, the first covering member 4 has a thermal expansion coefficient (linear expansion coefficient) after sintering larger than the thermal expansion coefficient of the lead 3. Specifically, it is larger than the thermal expansion coefficient (8.8 × 10 ⁻⁶ / K) when the lead 3 is an alloy containing platinum, usually 9 to 16 × 10 ⁻⁶ / K, preferably 9 to 14 ×. 10 ⁻⁶ / K, more preferably 9 to 11 × 10 ⁻⁶ / K.

  Therefore, for example, even when a high temperature is applied for firing the glass as described above and then cooled to room temperature, the first covering member 4 is not cracked or shattered, and the lead 3 is an electrode. The state firmly fixed to 2 can be maintained.

  Further, according to the temperature measuring element 10 having such a configuration, even when the product is shipped as a product and repeatedly subjected to heating and cooling during use, the first covering member 4 is not cracked or cracked. In addition, the connection and fixing of the electrode 2 and the lead 3 (joining by welding, brazing, or the like) is stably maintained for a long time. Therefore, the temperature sensing element 10 of the present embodiment can be a highly reliable and long-life temperature sensing element with less occurrence of problems such as a decrease in temperature detection accuracy and disconnection of the sensor.

  In addition, components other than platinum in the metal material mainly composed of platinum used for the lead 3 and the like are appropriately selected for the purpose of adjusting the temperature resistance coefficient (TCR) and improving heat resistance. ) And the addition amount are selected. Examples of components other than platinum include metal materials of platinum group elements such as palladium, rhodium and iridium, and gold.

The metal material mainly composed of platinum contains platinum in a proportion of about 80% by mass or more. In a metal material containing platinum as a main component, platinum and other components may form an alloy or may exist as independent crystal particles. In the case of the internal resistance wiring 5, an additive other than the metal component may be contained, and as the additive, for example, inorganic particles similar to those contained in the insulating layers 1 a and 1 b such as aluminum oxide. Etc. The additive is added to match the firing shrinkage rate between the internal resistance wiring 5 and the insulating layers 1a and 1b.

  As described above, the insulating layers 1a and 1b of the insulating base 1 are made of ceramic ceramics such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, and a glass ceramic sintered body. If it is formed by a ligation and is made of an aluminum oxide sintered body, it can be manufactured by the following method. First, a slurry prepared by adding and mixing an appropriate organic binder and solvent to raw powders such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide is formed into a sheet by a doctor blade method or the like to form a ceramic green sheet. Make it. Next, after cutting these ceramic green sheets into appropriate dimensions, a plurality of these are laminated to produce a laminate. Thereafter, the laminated body is fired at a high temperature (about 1600 ° C.), whereby the insulating layers 1a and 1b are manufactured. The plurality of ceramic green sheets become the insulating layers 1a and 1b, respectively.

When each insulating layer 1a, 1b produced as described above is made of an aluminum oxide sintered body, the thermal expansion coefficient (linear expansion coefficient) after sintering becomes smaller than the thermal expansion coefficient of the lead 3. ing. Specifically, it is set to ^{6 to} 8 × 10 ⁻⁶ / K, which is smaller than the thermal expansion coefficient (8.8 × 10 ⁻⁶ / K) when the lead 3 is an alloy containing platinum.

  In consideration of the thermal expansion coefficient of the first covering member 4, there is a relationship between them (thermal expansion coefficient of the first covering member> thermal expansion coefficient of the lead> thermal expansion coefficient of the insulating base). It comes to hold. As a result, the portion of the first covering member 4 [see FIG. 1 (a)] applied on the insulating layer 1a so as to protrude from the electrode 2 on the main surface of the temperature sensing element 10 is also on the electrode 2. As in the case of No. 1, the covering member does not crack or float after firing and cooling, and the first covering member 4 is kept in close contact with the main surface of the temperature sensing element 10. Therefore, the lead 3 is maintained. It is possible to reinforce the state in which is firmly bonded and fixed to the electrode 2.

  In addition, in order to make the adhesion of the first covering member 4 to the main surface of the temperature measuring body 10 more reliable, the application of the material (slurry) at the time of manufacturing the first covering member 4 described above is performed. In this case, this material may be applied to the edge of the insulating layer 1a so as to cover both corners 1c, 1c on the lead 3 side of the insulating base 1 (insulating layer 1a) shown in FIG. desirable. Thereby, the float and peeling of the coating | coated member after cooling which started from both corner | angular parts 1c and 1c can be prevented.

  In addition, the main surface of the temperature measuring body 10 (the upper surface of the insulating layer 1a) is previously subjected to a treatment such as plasma treatment or blasting for improving adhesion with the first covering member 4 or the electrode 2 or metal wiring. You can go there.

  The electrode 2 disposed on the upper surface of the insulating layer 1a is made of a metal material mainly composed of platinum or the like in consideration of stability at a high temperature. In consideration of adhesion to the lower insulating layer 1a (via conductor 6) and the upper lead 3, the electrode 2 preferably does not contain a glass component. When the glass component is not contained, the metal material of the electrode 2 and the metal material of the via conductor 6 connected to the electrode 2 are favorably connected during firing, which is preferable. Moreover, when it does not contain a glass component, when connecting the lead | read | reed 3 by resistance welding, the brazing method, etc., this can be joined favorably and it is preferable.

FIG. 2 is a view showing a temperature measuring body 20 according to the second embodiment of the present invention, in which (a) is a perspective view and (b).
FIG. 2 is an exploded perspective view of (a). In FIG. 2, constituent members having the same functions as those of the first embodiment described in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the example of FIG. 2, wiring (resistor) serving as resistance adjusting means of the temperature sensing element 20 is provided in a region (surface region 1 d on the left side in the drawing) other than the region where the electrode 2 is provided on the main surface (upper surface) of the insulating substrate 1. Adjustment wiring 1e) is provided, and as shown in FIG. 2 (b), a covering member that protects the resistance adjustment wiring 1e so as not to overlap the electrode 2 above the resistance adjustment wiring 1e. (Second covering member 7) is provided.

  The resistance adjustment wiring 1e is formed of a metal material mainly composed of the same metal material (platinum or the like) as the internal resistance wiring 5, and all of them including the auxiliary wiring for trimming are the main surface of the insulating substrate 1. When formed on the insulating layer 1a, the main portion of the resistance adjustment wiring is formed inside the insulating base 1 similarly to the internal resistance wiring 5, and the main surface of the insulating base 1 is used for trimming. There is a case where only the auxiliary wiring portion is disposed, and the auxiliary wiring and the main trunk wiring inside are connected by a via conductor for resistance adjustment wiring penetrating the insulating substrate 1 in the vertical direction.

  The second covering member 7 formed on the upper side of the resistance adjusting wiring 1e is made of a material similar to or similar to the first covering member 4 described above, but may be different. For example, barium silicate It is made of a glass material such as a system glass or borosilicate glass, and can be manufactured by the same method as the first covering member 4.

  Further, the second covering member 7 has a principal surface region close to the electrode 2 in a range not overlapping the electrode 2 [in FIG. 2B, the region other than the region where the electrode 2 is provided on the principal surface of the insulating substrate 1. After the first covering member 4 is manufactured, the end portion 7a on the electrode 2 side is under the first covering member 4 as shown in FIG. 2 (a). It has come to dive. That is, the first covering member 4 is formed so as to cover the end portion 7 a on the electrode 2 side of the second covering member 7.

The second covering member 7 has a thermal expansion coefficient (linear expansion coefficient) equal to or smaller than the thermal expansion coefficient of the first covering member 4 and the thermal expansion coefficient of the insulating layer 1a. Equal or larger. Specifically, the thermal expansion coefficient of the second covering member 7 is usually 2 to 16 × 10 ⁻⁶ / K, preferably 4 to 14 × 10 ⁻⁶ / K, more preferably 6 to 11 × 10 ^−6. / K.

  Therefore, the same effect as the first covering member 4 can be obtained. That is, for example, even when a high temperature is applied for baking the glass and then cooled to room temperature, the second covering member 7 is free from cracks and vibrations, and the connection between the lead 3 and the electrode 2 is fixed. The end of the first covering member 4 opposite to the lead side can be firmly joined by joining the glasses. Further, the insulating layer 1a side is also reliably bonded in the same manner.

  Therefore, even when the temperature measuring element 20 is shipped as a product and repeatedly heated and cooled at the time of use, the first covering member 4 and the second covering member 7 are not cracked or expanded. In addition, the reinforcement of the connection between the electrode 2 and the lead 3 by the first covering member 4 and the second covering member 7 is stably maintained over a long period of time. Thereby, the temperature sensing element 20 of the present embodiment can be a highly reliable and long-life temperature sensing element with less occurrence of problems such as a decrease in temperature detection accuracy and disconnection of the sensor.

When the thermal expansion coefficient of the lead 3 is taken into consideration, there is a gap between these members (thermal expansion coefficient of the first covering member> thermal expansion coefficient of the lead> thermal expansion coefficient of the second covering member> insulating substrate. The thermal expansion coefficient) relationship is established. By comprising in this way, reinforcement of connection fixation of the said electrode 2 and the said lead | read | reed 3 can be stably maintained over a long term in the optimal state.

  Further, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention. For example, there is a covering member made of ceramics.

DESCRIPTION OF SYMBOLS 1 ... Insulating base | substrate 1a .. Insulating layer 1b .. Insulating layer 1c .. Corner | angular part 1d .. Surface area 1e .. Resistance adjustment wiring 2 ... Electrode 3 ... Lead 4 ... 1st Cover member 5... Internal resistance wiring 6... Via conductor 6 a .. Top portion 7... Second cover member 7 a.

Claims (4)

An insulating substrate in which a plurality of insulating layers are laminated; an internal resistance wiring provided in the insulating substrate; an electrode provided on a main surface of the insulating substrate; A via conductor that connects the internal resistance wiring and the electrode; a lead connected to the electrode; and a first covering member made of a glass material that covers the electrode and the electrode side end of the lead. And
The temperature measuring element, wherein the first covering member has a thermal expansion coefficient larger than that of the lead. A resistance adjusting means disposed in a region other than the region where the electrode is provided on the main surface of the insulating base; and a second covering member made of a glass material covering the resistance adjusting means.
2. The first covering member is disposed so as to cover an end portion of the second covering member, the electrode, and an electrode side end portion of the lead. RTD.   The thermal expansion coefficient of the second covering member is smaller than the thermal expansion coefficient of the first covering member and larger than the thermal expansion coefficient of the insulating substrate. RTD.   The temperature measuring body according to claim 1, wherein the lead is made of platinum or a metal material containing platinum as a main component.