JP2007300065A - Thin film sensor, thin film sensor module, and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film sensor module and a thin film sensor in which surface roughness is not increased even by a thermal process after film formation, while obtaining superior electric properties. <P>SOLUTION: The thin film sensor comprises an insulating substrate, and a temperature-sensitive resistor laminated on the insulating substrate and made of a crystal of a platinum group metal. In the thin film sensor, surface roughness of the temperature-sensitive resistor is 0.1 μm or less, the ratio of the (111) plane of the crystal is 99% or more, and is oriented within 10° with respect to the perpendicular direction (ND direction) to the plane of the layer of the temperature-sensitive resistor, and further crystal grain diameter of the crystal is 0.3 μm or more. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thin film sensor, a thin film sensor module, and a thin film sensor manufacturing method.

  Conventionally, as a thin film sensor module that is used to perform functions such as a temperature sensor that measures the temperature of various objects or fluids, a temperature-sensitive resistor that detects the temperature by converting the amount of heat into an electrical signal is used. Is widely used. In particular, thin film sensor modules using platinum group elements having a large absolute value of resistance temperature coefficient in terms of sensitivity are widely used, but the present situation is that higher sensitivity is required.

  In general, it is known that the temperature coefficient of resistance of a resistor is affected by the presence form of crystals constituting the resistor (Non-Patent Document 1). For example, Patent Document 1 and Non-Patent Document 2 disclose a technique for increasing the sensitivity by increasing the grain size of a crystal constituting a resistor by, for example, heat-treating a laminated body after film formation. Has been.

  As a method of enlarging the grain size of the crystal constituting the temperature-sensitive resistor, first, a temperature-sensitive resistor material such as platinum is deposited on the substrate by forming a pattern by a lamination technique such as plating or vapor deposition, Examples thereof include a method in which a crystal is grown by heat treatment at about several hundred to 1,000 ° C.

  However, for the purpose of increasing sensitivity, it is possible to grow crystals under severe heat treatment conditions. However, in this case, the surface roughness of the thin film sensor increases, and the productivity decreases. Moreover, the present condition is that satisfactory electrical characteristics (resistance temperature coefficient; TCR, etc.) are not obtained only by heat treatment.

Patent Document 2 describes that a layer (for example) a titanium layer for improving the adhesion between a platinum thin film and a substrate is interposed between the two when a platinum thin film resistor is manufactured. .
Furthermore, in Patent Document 1, in a method for manufacturing a platinum thin film resistor, a platinum thin film or a titanium layer is provided while improving the adhesion of the platinum thin film to the substrate by interposing a titanium layer between the platinum thin film and the substrate. It has been described that oxygen can be mixed in the sputtering gas for forming the film to sufficiently improve the resistance temperature coefficient of the platinum thin film by high-temperature annealing.

However, there is room for further improvement in the adhesion between the platinum thin film and the substrate.
JP 2001-291607 A JP 11-354302 A “Structure and Physical Properties of Thin Films / Fine Particles”, Maruzen, pp. 139-156 (1974) “Development of high TCR platinum thin film”, IEEE Trans. SM. , 124, 7, 242-247 (2004)

  The present invention has been made in view of the above-described problems, and has a thin film sensor that does not increase surface roughness even after heat treatment after film formation while obtaining good electrical characteristics, and the thin film sensor. An object of the present invention is to provide a thin film sensor module and a method of manufacturing the thin film sensor.

  Another object of the present invention is to provide a thin film sensor having high sensitivity and a temperature-sensitive resistor that does not easily peel off, a thin film sensor module having the thin film sensor, and a method for manufacturing the thin film sensor.

The thin film sensor of the present invention is
An insulating substrate and a temperature sensitive resistor made of a platinum group metal crystal laminated on the insulating substrate;
The surface roughness Rz of the temperature sensitive resistor is 0.1 μm or less,
The ratio of the (111) plane of the crystal that is oriented within 10 ° with respect to the surface perpendicular direction (ND direction) of the layer of the temperature sensitive resistor is 99% or more,
The crystal grain size is 0.3 μm or more.

It is preferable that the crystal has a fibrous oriented structure, and in the fibrous oriented structure, the (111) plane of the crystal has a rotational axis in the direction perpendicular to the surface of the layer of the temperature sensitive resistor.
The platinum group metal is preferably platinum.

It is preferable that the thin film sensor further includes an adhesion layer made of a material mainly composed of a transition metal between the insulating substrate and the temperature sensitive resistor.
The thin film sensor preferably further includes a silicon compound layer made of a compound of silicon and an element selected from the group consisting of carbon, nitrogen, fluorine and oxygen between the insulating substrate and the adhesion layer.

  Examples of the thin film sensor include a sensor selected from the group consisting of a temperature sensor, a flow rate sensor, a specific heat sensor, a thermal conductivity sensor, a concentration sensor, a liquid type identification sensor, a strain sensor, a stress sensor, and a humidity sensor.

The thin film sensor module of the present invention includes the thin film sensor.
The manufacturing method of the thin film sensor of the present invention includes:
Laminating a temperature sensitive resistor on an insulating substrate to obtain a temperature sensitive laminate;
And heat-treating the temperature-sensitive laminate in an inert gas atmosphere having an oxygen partial pressure of 0.001 ppt or more and 1 ppm or less.

  According to the present invention, there is provided a thin film sensor, a thin film sensor module having the thin film sensor, and a method of manufacturing the thin film sensor without increasing surface roughness even by heat treatment after film formation while obtaining good electrical characteristics. Provided.

  According to one embodiment of the present invention, there are provided a thin film sensor, a thin film sensor module having the thin film sensor, and a method for manufacturing the thin film sensor, which are highly sensitive and the temperature sensitive resistor is hardly peeled off.

<Thin film sensor>
FIG. 1 is a schematic view of a thin film sensor (thin film chip) of the present invention. The thin film sensor 10 includes at least an insulating substrate 11 having electrical insulation and a temperature-sensitive resistor 14.

  As shown in FIG. 2, the thin film sensor 10 has an adhesive layer 13 between the insulating substrate 11 and the temperature sensitive resistor 14 for the purpose of improving the adhesion between the insulating substrate 11 and the temperature sensitive resistor 14. Further, the silicon compound layer 12 may be provided between the insulating substrate 11 and the adhesion layer 13. The thin film sensor 10 may have a protective film 16 on the surface of the thin film sensor 10 for the purpose of preventing physical damage to the thin film sensor. The thin film sensor 10 may include a bonding pad 18 that electrically connects the thin film sensor 10 and an external member.

In the present invention, the direction from the insulating substrate toward the temperature sensitive resistor may be referred to as “upper” for convenience.
The material of the insulating substrate 11 is not particularly limited as long as it is an insulating material, and examples thereof include silicon and alumina. The shape of the insulating substrate 11 can be various shapes. For example, the insulating substrate 11 may have a rectangular shape as shown in FIG. 1, an elliptical shape, or a circular shape. The film thickness of the insulating substrate 11 may be about 300 to 1,000 μm.

  The temperature-sensitive resistor 14 is not particularly limited as long as it is manufactured from a material having a large resistance temperature coefficient and being thermally stable. Examples of the material of the temperature-sensitive resistor 14 include platinum group elements (ruthenium, rhodium, Palladium, osmium, iridium, platinum) or a metal alloy containing at least one element as a main component or an alloy of these metals is used. In particular, platinum is more preferable from the viewpoints of film formation, stability of characteristics, and cost. The temperature sensitive resistor 14 may be formed into a desired film thickness or a desired pattern using such a material. For example, the film thickness may be about 0.1 to 1 μm.

The material of the adhesion layer 13 may be variously selected within the range and the material that does not affect the temperature-resistance characteristics of the insulating substrate 11, and examples thereof include a material mainly composed of a transition metal. May contain a metal other than a transition metal as a metal. Specific examples of the material mainly composed of this transition metal include titanium (Ti), chromium (Cr), TiO ₂ ,
TiBaO and the like can be mentioned, among which titanium and chromium are preferable from the viewpoint of adhesion. In the material mainly composed of transition metal, transition metal is usually contained in an amount of 10 to 100% by weight, preferably 60 to 100% by weight. The thickness of the adhesion layer is, for example, preferably 0.002 to 0.1 μm, and more preferably 0.005 to 0.05 μm.

The silicon compound layer 12 is made of a compound of silicon and an element selected from the group consisting of carbon, nitrogen, fluorine and oxygen. Such compounds include SiO ₂ , SiN, SiON
, SiC, SiOC, SiOF, etc. Among them, SiO _{2 is} particularly preferable from the viewpoint of film formation.
Is preferred.

The thickness of the silicon compound layer 12 is preferably 50 to 5,000 nm, more preferably 100 to 1,000 nm.
When the temperature sensitive resistor 14 is laminated on the insulating substrate 11 via the adhesion layer 13 and further the silicon compound layer 12, the temperature sensitive resistor 14 is firmly adhered to the insulating substrate 11 and hardly peeled off.

  The material of the protective film 16 is not particularly limited as long as it can achieve the above-described object, and examples thereof include resin and glass. Further, the thickness of the protective film 16 may be about 1 μm.

  The material of the bonding pad 18 is not particularly limited as long as it has good conductivity, and examples thereof include gold (Au) and platinum. Further, the bonding pad 18 may have various shapes depending on an applied form, for example, a shape of about 0.2 × 0.15 mm in length and width and about 0.1 μm in thickness.

<Presence form of crystal of temperature-sensitive resistor in the present invention>
In the thin film sensor of the present invention, the crystals constituting the temperature sensitive resistor exist in a form having a specific orientation. In the present invention, this orientation state is defined by “orientation” described below. In the present invention, “orientation” means (111) of crystals oriented within 10 ° from the surface perpendicular direction (ND direction) of the layer of the temperature sensitive resistor (that is, crystals constituting the temperature sensitive resistor). ) The ratio of the surface. In the thin film sensor of the present invention, this ratio is 99% or more. If it is less than 99%, unless the crystal grains are coarsened, a sufficient resistance temperature coefficient cannot be obtained, and high sensitivity of the thin film sensor cannot be achieved. The “orientation” value is a value obtained by the method described in the column of Examples described later.

  In general, it is known that the crystalline state of the temperature-sensitive resistor affects the change in resistance value accompanying the temperature rise in the temperature-sensitive resistor. It is known that the gradient of the temperature coefficient of resistance increases as the crystal state, particularly the crystal grain size, increases. The increase in grain size is widely used as one of the techniques for increasing the sensitivity of thin film sensors. Yes.

  On the other hand, in the present invention, attention is paid to the existence form of crystals constituting the temperature sensitive resistor. That is, the present inventors have found that the temperature coefficient of resistance of the temperature-sensitive resistor is improved by controlling the crystal form, particularly the crystal orientation. As in the present invention, the mechanism of improving the temperature coefficient of resistance by controlling the orientation is not clear, but it is considered that the electrical characteristics of the crystal can be improved by aligning the crystal orientation in a specific direction. It is done.

  Further, the crystal constituting the temperature sensitive resistor has a fibrous oriented structure, and in the fibrous oriented structure, the (111) plane of the crystal is set with the plane perpendicular to the layer of the temperature sensitive resistor as the rotation axis. Preferably it is. By having such a structure, the electrical characteristics are further improved. In addition, what is necessary is just to observe for the observation of this fibrous orientation structure | tissue using the various methods used for structure | tissue observation, for example, you may observe using the following EBSD evaluation apparatus.

  In the present invention, the crystal orientation was evaluated using the EBSD (Backscattered Electron Diffraction Pattern) method. An X-ray diffractometer (XRD) is generally used to evaluate the crystal structure of inorganic materials, but this device can only obtain average information of the entire crystal structure, It is not possible to evaluate the existence form of the individual crystal grains constituting. On the other hand, in order to evaluate the orientation of individual crystal grains, a transmission electron microscope (TEM) is generally used. However, statistical evaluation of crystal grains included in a crystal structure is performed. Really impossible.

On the other hand, if an EBSD evaluation apparatus is used, it is possible to quickly evaluate the existence form of individual crystal grains, and it is possible to evaluate crystal grain size, grain size distribution, crystal orientation, strain calculation, and the like.
In the thin film sensor of the present invention, the surface roughness (Rz) of the temperature sensitive resistor is 0.1 μm or less, more preferably 0.07 μm or less, and the lower limit is not particularly limited, but is usually 0.01 μm. Degree. If the surface roughness (Rz) is larger than the above range, a constant electrical characteristic cannot be obtained during pattern molding, and productivity is also lowered.

  The grain size of the crystals constituting the temperature sensitive resistor is 0.3 μm or more, more preferably 0.4 μm or more, and the upper limit is not particularly limited, but is usually about 5.0 μm. In addition, the value of this “crystal grain size” is a value obtained by the method described in the column of Examples described later.

The resistance temperature coefficient of the thin film sensor of the present invention is preferably 3,000 ppm / K or more, more preferably 3,300 ppm / K or more, and the upper limit is about 3,900 ppm / K.

  The thin film sensor of the present invention can be used in an apparatus for measuring an index that affects the resistance value of a temperature sensitive resistor. Examples thereof include a temperature sensor, a flow rate sensor, a specific heat sensor, a heat conduction Examples include a sex sensor, a concentration sensor, a liquid type identification sensor, a strain sensor, a stress sensor, and a humidity sensor.

<Manufacturing method of thin film sensor>
The manufacturing method of the thin film sensor of this invention is demonstrated. In the production of the thin film sensor of the present invention, first, a temperature sensitive resistor is laminated on an insulating substrate by vapor deposition means such as sputtering to form a temperature sensitive laminate. This temperature-sensitive laminate is heat-treated to obtain a thin film sensor.

  First, the above-described stacking conditions will be described. There is no restriction | limiting in particular as this lamination | stacking means / condition, Sputtering, vapor deposition, etc. are illustrated. For example, when a temperature-sensitive laminate is produced by sputtering, the conditions such as the degree of vacuum and pressure during sputtering are not particularly limited. For example, an oxygen gas may be mixed with an inert gas such as argon as an introduction gas during sputtering. The amount of oxygen mixed with the inert gas can be, for example, in the range of 0.5 to 30% by volume in the standard state, and preferably in the range of 2 to 20% by volume. If it is less than 0.5% by volume, a part of the metal atoms constituting the adhesion layer diffuses into the temperature-sensitive resistor, and the temperature coefficient of resistance (TCR) decreases. When it is 30% by volume or more, oxygen is dissolved in the crystal constituting the temperature-sensitive resistor, and thus its TCR is lowered.

If a platinum thin film is formed as the temperature sensitive resistor, for example, vapor deposition can be performed under the following conditions.
Vapor deposition means: Sputtering method Apparatus: Magnetron sputtering apparatus Ultimate vacuum: 6.0 × 10 ⁻⁵ Pa or less Film forming pressure: 0.1 to 0.8 Pa
Gas flow rate: 10-180 SCCM
Deposition power: 400-1400W
Deposition temperature: room temperature to 250 ° C.

  When a thin film sensor is provided with an adhesion layer, the adhesion layer is laminated on the insulating substrate using a lamination technique such as sputtering before laminating the temperature sensitive resistor, and then the temperature sensing resistor is laminated as described above. do it. After the adhesion layer is stacked, it is preferable to perform the subsequent steps without being exposed to air, oxygen, moisture, or the like. The stacking condition of the adhesion layer is not particularly limited as long as the adhesion is ensured and the resistance temperature characteristics of the temperature sensitive resistor are not affected or particularly adversely affected.

If a titanium (Ti) layer is formed as the adhesion layer, for example, vapor deposition can be performed under the following conditions.
Vapor deposition means: Sputtering method Apparatus: Magnetron sputtering apparatus Ultimate vacuum: 6.0 × 10 ⁻⁵ Pa or less Film forming pressure: 0.1 to 2 Pa
Gas flow rate: 10-180 SCCM
Deposition power: 400-1400W.

When the silicon compound layer is provided on the thin film sensor, the silicon compound layer is laminated on one surface of the insulating substrate before the adhesion layer is laminated.
The silicon compound layer can be formed by means such as a sol-gel method, a spin coating method, a CVD method, or a sputtering method. Specifically, for example, it can be produced under the following conditions.

Lamination means: Spin coating method Equipment: Spin coater Raw material: Coating type SiO ₂ film forming material (SOG)
Rotation speed: 1,000-6,000 rpm
Temperature: 450-1,000 ° C.

  Next, the above heat treatment will be described. In this heat treatment, the oxygen partial pressure is applied to the temperature-sensitive laminate obtained as described above (that is, a laminate comprising an insulating substrate and a temperature-sensitive resistor, and an optional adhesion layer and an optional silicon compound layer). Annealing is performed in an inert gas atmosphere in which is 0.001 ppt or more and 1 ppm or less. As the inert gas, an inert gas may be appropriately selected with respect to the material constituting the insulating substrate, the adhesion layer, and / or the temperature sensitive resistor, and argon is preferable. The purity of the inert gas is desirably 99.9999% or more. When the oxygen partial pressure is higher than the above range, the surface roughness such as arithmetic average roughness (Ra) and ten-point average roughness (Rz) of the temperature-sensitive resistor after heat treatment increases, and the productivity of the thin film sensor increases. It will decline. On the other hand, if it is less than 0.001 ppt, special equipment or the like is required to realize this atmosphere, resulting in an increase in production cost.

  The annealing temperature is, for example, about 900 ° C. to about 1100 ° C. When the annealing temperature is less than 900 ° C., the characteristic of the temperature coefficient of resistance of the obtained thin film sensor tends to be lowered. Moreover, when it exceeds 1100 degreeC, it exists in the tendency for the surface state of the thin film sensor obtained to deteriorate. The annealing time can be, for example, 4 hours or more and less than 8 hours. If the annealing time is longer than 8 hours, the crystal grains of platinum are excessively coarsened, the surface roughness is increased, and the uniformity in the substrate material tends to be lowered. On the other hand, when the annealing time is less than 4 hours, that is, too short, the rate of change with time of the resistance value of the temperature-sensitive resistor tends to increase.

  The temperature sensitive resistor may be formed into various patterns by means such as etching. For example, the temperature sensitive resistor may be processed into a meandering pattern shape having a width of, for example, 5 to 25 μm and a total length of, for example, 4 to 23 cm by an etching method or the like.

  The temperature-sensitive laminate thus obtained may be provided with a protective film 16, a bonding pad 18 and the like as necessary as described above. As a method of providing these, a method known in this technical field may be used.

<Thin film sensor module>
Next, the thin film sensor module of the present invention will be described. The thin film sensor module of the present invention includes a member that is thermally connected to an object or a fluid to be measured, the above-described thin film sensor that is thermally connected to the member, and the thin film sensor that is electrically connected to the thin film sensor. Member. This configuration is illustrated in FIG. 3 and FIG.

  FIG. 3 is a schematic view illustrating a thin film sensor module (for example, a temperature sensor module) of the present invention, and FIG. 4 is a schematic cross-sectional view illustrating a thin film sensor module (for example, a temperature sensor module) of the present invention. (A) is a plan longitudinal sectional view, and (b) is a lateral longitudinal sectional view. The thin film sensor module (for example, temperature sensor module) 20 of the present invention has a thin film sensor (for example, temperature sensor) 10 in which a fin plate 24 and an output terminal 26 are fixed inside a housing 22.

Various materials can be used as the material of the housing 22 as long as the material has low thermal conductivity. In addition, materials imparted with chemical resistance and oil resistance can be used according to the object or fluid to be measured. Examples having these characteristics include epoxy resin, polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and the like. Moreover, what is necessary is just to make the shape of a thin film sensor module into various forms according to the aspect to which a thin film sensor module is applied. For example, as shown in FIGS. 3 and 4B, the housing 22 has a first large-diameter portion 34 from which the output terminal 26 protrudes, and a second large-diameter portion positioned below the first large-diameter portion 34 with a gap therebetween. A diameter portion 36 may be provided, and a notch portion 38 for forming a heat insulating space may be provided between the first large diameter portion 34 and the second large diameter portion 36. The housing 22 is not limited to this form.

  The fin plate 24 is not particularly limited as long as it is made of a material having good thermal conductivity, and is made of, for example, copper, aluminum, tungsten, duralumin, a copper-tungsten alloy, or the like. Further, the fin plate 24 may have various shapes as appropriate according to the application of the thin film sensor module, and may be a thin plate having a thickness of about 200 μm, for example. In addition, as a material for adhering the fin plate 24 and the thin film sensor 10, any material can be used as long as it has a thermal conductivity, for example, a silver paste.

  The output terminal 26 is not particularly limited as long as it is made of a conductive material, and examples of this material include copper and aluminum. The output terminal 26 is electrically connected to the thin film sensor 10 via the bonding wire 32. In FIG. 3, the shape of the output terminal 26 protrudes from the resin housing 2 so as to protrude from the resin housing 2 in a straight line and juxtaposed in one line. Although the length is shown as gradually increasing (gradually decreasing), it may be formed into various shapes depending on the form to be applied. 3, the sensor pressing plate for pressing the thin film sensor module 20 from above and the flow rate detection circuit board connected to the output terminal 26 to form a circuit can be easily mounted. Further, the risk of damaging the thin film sensor module 20 when the sensor pressing plate and the flow rate detection circuit board are attached is reduced.

[Example]
Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the examples.

(Reference example)
A 300 nm-thick SiO ₂ layer was formed on an alumina substrate (size: disk with a diameter of 100 mm, thickness: 385 μm) by the spin coating method under the following conditions.

Equipment: Spin coater Ingredients: Coating type SiO ₂ film forming material
(Manufactured by Tokyo Ohka Kogyo Co., Ltd., raw material: OCD (trade name), siloxane-based material)
Rotational speed: 1,000 rpm x 5 s → 5,000 rpm x 30 s
Temperature: 695 ° C.

Next, sputtering was performed on the SiO ₂ layer thus formed using metal titanium (purity: 99.99%) as a target under the following conditions to form a titanium layer having a thickness of 30 nm.

Apparatus: Magnetron sputtering apparatus Ultimate vacuum: less than 6.0 × 10 ⁻⁵ Pa Deposition pressure: 0.86 Pa
Gas flow rate: 180 SCCM [Ar: O ₂ = 10: 0 (volume ratio in the standard state)]
Deposition power: 1,000 W (DC)
Deposition temperature: 250 ° C.

  Next, sputtering was performed on the titanium layer thus formed using platinum (purity 99.9%) as a target under the following conditions to form a 400 nm-thick temperature sensitive resistor.

Apparatus: Magnetron sputtering apparatus Ultimate vacuum: less than 6.0 × 10 ⁻⁵ Pa Deposition pressure: 0.18 Pa
Gas flow rate: 10 SCCM [Ar: O ₂ = 9: 1 (volume ratio in standard state)]
Deposition power: 500W (RF)
Deposition temperature: 250 ° C.

The reference temperature coefficient (TCR), Ra and Rz, and adhesion as described below were measured for the reference laminate thus obtained. The results are shown in Table 1.
Example 1
The argon gas was purified to obtain purified argon gas having an argon purity of 99.9999% or more and an oxygen partial pressure of less than 0.1 ppm in the standard state. In this purified argon gas, the above reference laminate was heat-treated at 1,000 ° C. for 4 hours to obtain a thin film sensor 1. The thin film sensor 1 was measured for the temperature coefficient of resistance (TCR), Ra and Rz, and adhesion as described below. The results are shown in Table 1.

(Comparative Example 1)
In Example 1, heat treatment was performed in the same manner as in Example 1 except that the heat treatment conditions were changed to 4 hours at an oxygen partial pressure of 20% and 900 ° C. in an air atmosphere to obtain a comparative thin film sensor 1. With respect to this comparative thin film sensor 1, the following resistance temperature coefficient (TCR), Ra and Rz, and adhesion were measured. The results are shown in Table 1.

(Comparative Example 2)
A comparative thin film sensor 2 was obtained in the same manner as in Comparative Example 1 except that the heat treatment temperature was changed to 1,000 ° C. in Comparative Example 1. The comparative thin film sensor 2 was measured for the temperature coefficient of resistance (TCR), Ra and Rz, and adhesion as described below. The results are shown in Table 1.

(Comparative Example 3)
In Example 1, heat treatment was performed in the same manner as in Example 1 except that the heat treatment conditions were changed to 4 hours at 900 ° C. under an oxygen partial pressure of less than 2 ppm in a vacuum atmosphere, whereby a comparative thin film sensor 3 was obtained. The comparative thin film sensor 3 was measured for the temperature coefficient of resistance (TCR), Ra and Rz, and adhesion as described below. The results are shown in Table 1.

(Comparative Example 4)
In Comparative Example 3, the heat treatment was performed in the same manner as in Comparative Example 3 except that the heat treatment temperature was changed to 1,000 ° C., and a comparative thin film sensor 4 was obtained. The comparative thin film sensor 4 was measured for the following temperature coefficient of resistance (TCR), Ra and Rz, and adhesion. The results are shown in Table 1.

<Measurement of resistance temperature coefficient (TCR)>
About the laminated body and thin film sensor used as object, the resistance temperature coefficient (TCR) was measured from the measurement of specific electrical resistance ρ-T characteristic.

In the present application, the resistance temperature coefficient is a value represented by the following (Equation 1).
(Formula 1): α = (1 / R) × (dR / dT) × 10 ⁶
α: Temperature coefficient of resistance (ppm / ° C)
T: Any absolute temperature (K)
R: Zero load resistance value (Ω) at T (K).

<Measurement of surface roughness Ra and Rz>
The surface roughness Ra was measured for each of the above-described thin film sensors and laminates with an optical interference type three-dimensional structural analysis microscope (New View 5032, manufactured by Zygo). For the measurement, a 100 × Mirau lens was used with white light, and a range of 54 × 72 μm was measured. Surface roughness Ra and Rz were obtained from the three-dimensional measurement surface thus obtained.

<Crystal grain size>
The longitudinal sections of the laminate and the thin film sensor manufactured as described above were smoothed by polishing and using a focused ion beam (FIB). About this smoothed longitudinal section, an FE gun type scanning electron microscope (JSM-6700F or JSM-7000F, manufactured by JEOL Ltd.) equipped with an EBSD evaluation apparatus (OIM Analysis, manufactured by TSL Solutions Co., Ltd.) and Using the attached EBSD analyzer, image data of a crystal state pattern was obtained according to the EBSD method. With respect to this image data, an analysis menu “Grain Size” of the EBSD analysis program (OIM Analysis, same as above) was selected, crystal grains having a crystal rotation angle of 5 ° or more were observed, and crystal grain size (μm) was calculated. The crystal grain size was calculated considering the Σ3 grain boundary indicating the twin grain boundary as an intragranular defect.

<Orientation>
The longitudinal sections of the laminate and the thin film sensor manufactured as described above were smoothed using polishing and a focused ion beam (FIB). Using an FE gun type scanning electron microscope (JSM-6700F or JSM-7000F, manufactured by JEOL Ltd.) equipped with an EBSD evaluation device (OIM Analysis, manufactured by TSL Solutions, Inc.) and an attached EBSD analysis device, With respect to this smoothed longitudinal section, image data of a crystal state pattern was obtained according to the EBSD method. This image data is selected from the analysis menu “Crystal Direction” of the EBSD analysis program (OIM Analysis, same as above), the “ND direction” of the laminated body or thin film sensor, and the (111) plane orientation of the platinum crystal of the temperature sensitive resistor. Analysis was performed under the condition of calculating the ratio of crystal grains with respect to all crystal grains within 10 degrees, and this ratio was defined as “orientation”. Note that a grain rotation angle of 5 ° or more was regarded as a crystal grain boundary, and an aggregate within 5 ° was recognized as one crystal grain.

<Adhesion>
About each of the laminated body manufactured as mentioned above and the thin film sensor, the adhesiveness of an insulated substrate and a temperature sensitive resistor was evaluated with the following wire pull test methods.
* Wire Pull Test Method A gold wire (25 μmφ) was bonded (bonded) on a gold electrode pad (18) of a thin film chip (thin film sensor). Thereafter, the gold wire was pulled with a force of about 10 g in the vertical direction of the thin film chip at room temperature. The evaluation criteria are as follows.

AA: The gold electrode pad and the temperature sensitive resistor did not peel from the gold wire, and the gold wire was broken.
CC: The gold electrode pad and the temperature sensitive resistor were peeled from the gold wire.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments, various modifications and changes may be made to the embodiments without departing from the broad spirit and scope of the invention as defined in the claims. Obviously you can. In other words, the present invention should not be construed as being limited by the details of the specific examples and the accompanying drawings.

It is a schematic diagram of one mode of a thin film sensor (thin film chip). It is a schematic diagram of one mode of a thin film sensor (thin film chip). It is the schematic which illustrated the thin film sensor module of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic sectional drawing which illustrated the thin film sensor module of this invention, Comprising: (a) is a plane longitudinal cross-sectional view, (b) is a side longitudinal cross-sectional view.

Explanation of symbols

10 Thin film sensor (thin film chip)
DESCRIPTION OF SYMBOLS 11 Insulating substrate 12 Silicon compound layer 13 Adhesion layer 14 Temperature sensitive resistor 16 Protective film 18 Bonding pad 20 Thin film sensor module 22 Housing 24 Fin plate 26 Output terminal 32 Bonding wire 34 1st large diameter part 36 2nd large diameter part 38 Notch Part

Claims (8)

An insulating substrate and a temperature sensitive resistor made of a platinum group metal crystal laminated on the insulating substrate;
The surface roughness Rz of the temperature sensitive resistor is 0.1 μm or less,
The ratio of the (111) plane of the crystal that is oriented within 10 ° with respect to the surface perpendicular direction (ND direction) of the layer of the temperature sensitive resistor is 99% or more,
A thin film sensor, wherein the crystal grain size is 0.3 μm or more.   2. The crystal according to claim 1, wherein the crystal has a fibrous orientation structure, and in the fibrous orientation structure, a (111) plane of the crystal has a rotational axis in a plane perpendicular to the layer of the temperature sensitive resistor. The thin film sensor described in 1.   The thin film sensor according to claim 1, wherein the platinum group element is platinum.   The thin film sensor according to claim 1, further comprising an adhesion layer made of a material mainly composed of a transition metal between the insulating substrate and the temperature sensitive resistor.   The silicon compound layer comprising a compound of silicon and an element selected from the group consisting of carbon, nitrogen, fluorine and oxygen is further provided between the insulating substrate and the adhesion layer. Thin film sensor.   6. A sensor selected from the group consisting of a temperature sensor, a flow sensor, a specific heat sensor, a thermal conductivity sensor, a concentration sensor, a liquid type identification sensor, a strain sensor, a stress sensor, and a humidity sensor. The thin film sensor according to any one of the above.   A thin film sensor module comprising the thin film sensor according to claim 1. Laminating a temperature sensitive resistor on an insulating substrate to obtain a temperature sensitive laminate;
The thin film sensor according to any one of claims 1 to 6, further comprising a step of heat-treating the temperature-sensitive laminate in an inert gas atmosphere having an oxygen partial pressure of 0.001 ppt or more and 1 ppm or less. Production method.

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