JP2018139240A - Thin film thermistor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film thermistor capable of inhibiting short circuit due to scattering matter, even if the comb-teeth itself of a comb side electrode or its connection is cut by laser trimming, and to provide a manufacturing method thereof.SOLUTION: A thin film thermistor includes an insulating base material 2, a thermistor film 3 formed on the insulating base material, and a pair of interdigital electrodes 4A, 4B formed oppositely on the thermistor film. One of the pair of interdigital electrodes has multiple one side comb-teeth 5A, and one side proximal end connection 6A connected with the proximal ends of the multiple one side comb-teeth, and the other of the pair of interdigital electrodes has multiple the other side comb-teeth 5B, and the other side proximal end connection 6B connected with the proximal ends of the other side comb-teeth. The one side comb-teeth is shorter than the other side comb-teeth, the distance L1 of the one side comb-teeth and the other side proximal end connection is longer than the distance L2 of the other side comb-teeth and the front side proximal end connection, and the proximal end of the other side comb-teeth or a part of the other side proximal end connection is a cutting part C for trimming.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thin film thermistor used for, for example, an infrared detection sensor and a method for manufacturing the same.

Conventionally, in a thin film thermistor used for an infrared detection sensor or the like, a method of performing laser trimming is known in order to improve the resistance value yield. For example, Patent Document 1 proposes a thermistor element in which a trimming cutting portion is provided outside a comb-shaped electrode in order to adjust a resistance value. Further, Patent Document 2 proposes a thin film thermistor in which a trimming cutting portion is provided on a resistance value adjusting metal pattern extending from an extraction electrode.
Thus, as a resistance value adjusting means, a method of adjusting a resistance value by cutting a resistance value adjusting electrode by laser trimming in a thin film thermistor has been conventionally used.

JP 2001-35705 A JP 2003-173901 A

The following problems remain in the conventional technology.
In the techniques of Patent Documents 1 and 2, the resistance value is adjusted by the trimming cut portion provided outside the comb electrode without cutting the comb tooth portion itself of the comb electrode, and therefore only fine adjustment of the resistance value is performed. There was an inconvenience that it was not possible.
Further, when the comb tooth portion itself of the comb electrode is cut, there is a possibility that scattered matter scattered by laser trimming may short-circuit the pair of comb electrodes. The scattered matter is a metal such as Au constituting the comb-shaped electrode or a material of the thermistor film as the base, and is scattered around and attached to the trimming cutting portion.
For example, as shown in FIG. 5A, in a thin film thermistor 100 including a pair of comb-shaped electrodes 104 that are patterned to face each other on the thermistor film 3 formed on the insulating substrate 2, When adjusting the resistance value by cutting the comb-tooth portion 105 of the comb-shaped electrode 104 at the base end portion, as shown in FIG. 5B, the comb-tooth portion 105 adjacent to the trimming cutting portion C and In some cases, scattered matter adheres between the opposing base end connection portions 106 and the pair of comb-shaped electrodes 104 are short-circuited and energized. In addition, in the figure, the range in which the scattered matter is likely to be scattered is surrounded by a two-dot chain line.

  The present invention has been made in view of the above-described problems, and a thin film thermistor capable of suppressing a short circuit due to scattered matter even when it is cut by laser trimming at the comb-teeth portion itself of the comb-side electrode or its connection portion, and its manufacture It aims to provide a method.

  The present invention employs the following configuration in order to solve the above problems. That is, the thin film thermistor according to the first invention includes an insulating base material, a thermistor film formed on the insulating base material, and a pair of comb-shaped electrodes patterned on the thermistor film so as to face each other. One of the pair of comb-shaped electrodes, one side base end connection in which a plurality of one side comb teeth extending in the opposing direction and a plurality of one side comb teeth are connected to the base end The other side of the pair of comb-shaped electrodes, the other side of which is connected to the plurality of other comb-tooth portions extending in the facing direction, and the base ends of the plurality of other-side comb-tooth portions A plurality of the one-side comb teeth and the plurality of the other-side comb teeth arranged alternately one by one, and the one-side comb teeth are the other The distance between the one side comb tooth portion and the other side proximal end connecting portion is shorter than the side comb tooth portion, and the other side comb tooth A trimming cutting part that is set longer than the distance between the first side base end connection part and at least one base end part of the other side comb tooth part or a part of the other side base end connection part. It is said that it is said.

  In this thin film thermistor, the one-side comb-tooth portion is shorter than the other-side comb-tooth portion, and at least one base-side portion of the other-side comb-tooth portion or a part of the other-side base-end connecting portion is cut. Since it is a cutting part, even if the cutting is performed by laser trimming and scattered objects are scattered around, the distance between the one side comb tooth part and the other side base end connection part is the same as the other side comb tooth part and the one side base part. The short circuit between electrodes can be suppressed by extending longer than the distance with an end connection part.

The thin film thermistor according to a second aspect of the present invention is the thin film thermistor according to the first aspect, wherein the other-side base end connecting portion is disposed outside the thermistor film, and the trimming cutting portion is also disposed outside the thermistor film. It is characterized by being.
That is, in this thin film thermistor, the other-side base end connecting portion is arranged outside the thermistor film, and the trimming cutting portion is also arranged outside the thermistor film. Since there is no thermistor film, the material of the thermistor film does not scatter and the short circuit can be further suppressed.

A method for manufacturing a thin film thermistor according to a third invention includes a thin film forming step of forming a thermistor film on an insulating substrate, and a comb electrode forming step of forming a pattern by making a pair of comb electrodes face each other on the thermistor film And a resistance adjusting step for adjusting a resistance value between the pair of comb-shaped electrodes, and one of the pair of comb-shaped electrodes, a plurality of one-side comb teeth extending in the facing direction, and a plurality of comb-shaped electrodes A plurality of other comb-teeth portions extending in the opposite direction, the other of the pair of comb-shaped electrodes. And a plurality of the other side comb tooth portions and a plurality of the one side comb tooth portions and a plurality of the other side comb tooth portions. When the one side comb-tooth portion is shorter than the other side comb-tooth portion, A distance between the one-side comb-tooth portion and the other-side proximal end connection portion is set to be longer than a distance between the other-side comb-tooth portion and the one-side proximal end connection portion; A base end portion of one of the other side comb tooth portions or a part of the other side base end connecting portion is cut with a laser beam.
That is, in this thin film thermistor manufacturing method, in the resistance adjustment step, the base end portion of the other side comb-tooth portion set as described above or a part of the other side base end connection portion is cut with a laser beam. Even if scattered around, the short-circuit between the electrodes can be suppressed because the inter-electrode distance between the one-side comb-tooth portion and the other-side base end connection portion is long.

The present invention has the following effects.
That is, according to the thin film thermistor and the manufacturing method thereof according to the present invention, the one side comb tooth portion is shorter than the other side comb tooth portion, and the base end portion or the other side base end connection of at least one other side comb tooth portion. Since part of the part is a cut part for trimming, the distance between the one-side comb tooth part and the other-side base end connecting part is small even if the scattered object is scattered by cutting with laser trimming. Moreover, the short circuit between electrodes can be suppressed by extending longer than the distance of the other side comb-tooth part and the one side base end connection part.
Therefore, in the thin film thermistor of the present invention, even if the comb tooth portion of the comb electrode itself or its connection portion is cut, it is possible to suppress a short circuit due to scattered matter, and to greatly adjust the resistance value, and to achieve high reliability. It is possible to produce a product having resistance adjustment.

In 1st Embodiment of the thin film thermistor which concerns on this invention, and its manufacturing method, it is the top view (a) after laser trimming, and the enlarged plan view (b) of the principal part. In 1st Embodiment, it is a top view which shows a manufacturing method in order of a process. In 2nd Embodiment of the thin film thermistor which concerns on this invention, and its manufacturing method, it is the top view (a) which shows the state which laser-trimmed the base end part of the comb-tooth part, and the enlarged plan view (b) of the principal part. In 2nd Embodiment, it is the top view (a) which shows the state which laser-trimmed the base end connection part, and the enlarged plan view (b) of the principal part. In the conventional example of the thin film thermistor and its manufacturing method concerning this invention, it is the top view (a) after laser trimming, and the enlarged plan view (b) of the principal part. It is explanatory drawing by a schematic cross section.

  Hereinafter, a first embodiment of a thin film thermistor and a method for manufacturing the same according to the present invention will be described with reference to FIGS. Note that in some of the drawings used for the following description, the scale is appropriately changed as necessary to make each part recognizable or easily recognizable.

As shown in FIG. 1, the thin film thermistor 1 of the present embodiment is patterned so as to face each other on an insulating substrate 2, a thermistor film 3 formed on the insulating substrate 2, and the thermistor film 3. And a pair of comb electrodes 4A and 4B.
One of the pair of comb-shaped electrodes 4A and 4B (comb-shaped electrode 4A) is connected to the plurality of one-side comb-tooth portions 5A extending in the facing direction and the base ends of the plurality of one-side comb-tooth portions 5A. One side proximal end connecting portion 6A.

The other of the pair of comb-shaped electrodes 4A and 4B (comb-shaped electrode 4B) is connected to the plurality of other-side comb-tooth portions 5B extending in the facing direction and the base ends of the plurality of other-side comb-tooth portions 5B. It has the other side base end connection part 6B.
The one-side base end connection portion 6 </ b> A and the other-side base end connection portion 6 </ b> B are disposed on both sides of the thermistor film 3.

The plurality of one-side comb-tooth portions 5A and the plurality of other-side comb-tooth portions 5B are alternately arranged side by side.
Further, the one-side comb-tooth portion 5A is shorter than the other-side comb-tooth portion 5B, and the distance L1 between the one-side comb-tooth portion 5A and the other-side proximal end connection portion 6B is equal to the other-side comb-tooth portion 5B and one-side. It is set longer than the distance L2 with the base end connection portion 6A. That is, the pair of comb-shaped electrodes 4A and 4B have comb teeth portions that are asymmetric with respect to each other.

Further, a base end portion of at least one other-side comb tooth portion 5B or a part of the other-side base end connection portion 6B is the cut trimming cutting portion C.
In the present embodiment, for example, as shown in FIG. 1, the base end portions of the three other comb teeth portions 5B on the right side in the drawing are trimmed cutting portions C, and the other comb teeth portions 5B are cut at these portions. Has been.
The distance L2 between the one-side comb-tooth portion 5A and the other-side base end connection portion 6B is preferably set to be longer than the range in which scattered matter scatters when laser trimming is performed at the trimming cutting portion C.

  As the insulating base material 2, base materials formed of various insulating materials can be used. For example, a rectangular insulating film is used. The insulating film is formed of, for example, a polyimide resin sheet having a thickness of 7.5 to 125 μm. In addition, as the insulating film, PET: polyethylene terephthalate, PEN: polyethylene naphthalate, LCP: liquid crystal polymer, or the like can be used.

The thermistor film 3 is a flexible thermistor film, for example, an M-Al-N film (where M represents at least one of Ti, V, Cr, Mn, Fe, Co, Ni and Cu). ).
That is, the thermistor film 3 has a general formula: M _x Al _y N _z (where M represents at least one of Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. 0.70 ≦ y / ( x + y) ≦ 0.98, 0.4 ≦ z ≦ 0.5, x + y + z = 1), and its crystal structure is a hexagonal wurtzite single phase. For these films, flexibility and good thermistor properties have been confirmed. The thermistor film 3 may contain oxygen as long as the thermistor characteristics are not significantly changed.

In the present embodiment, the thermistor film 3 formed in a rectangular shape with a Ti—Al—N thermistor material is employed. That is, the thermistor film 3 is formed by metal nitriding represented by the general formula: Ti _x Al _y N _z (0.70 ≦ y / (x + y) ≦ 0.95, 0.4 ≦ z ≦ 0.5, x + y + z = 1). The crystal structure of this is a hexagonal wurtzite single phase.

The pair of comb-shaped electrodes 4A and 4B has, for example, a Cr or NiCr bonding layer having a film thickness of 5 to 100 nm and an electrode layer formed on the bonding layer by a noble metal such as Au and having a film thickness of 50 to 1000 nm. Yes.
Although not shown in FIG. 1, a pair of pattern wirings connected to the pair of comb-shaped electrodes 4 </ b> A and 4 </ b> B for connection to external wirings may be formed on the insulating substrate 2.

In the manufacturing method of the thin film thermistor 1 of the present embodiment, a thin film forming step of forming the thermistor film 3 on the insulating substrate 2 and a pair of comb-shaped electrodes 4A and 4B are formed on the thermistor film 3 so as to face each other. A comb-shaped electrode forming step and a resistance adjusting step of adjusting a resistance value between the pair of comb-shaped electrodes 4A and 4B.
In the resistance adjusting step, the base end portion of at least one other-side comb tooth portion 5B or a part of the other-side base end connection portion 6B is cut with a laser beam.

As a more specific example of the manufacturing method, a reactive sputtering method is performed in a nitrogen-containing atmosphere using a Ti—Al alloy sputtering target on the insulating base material 2 (on one surface) of a polyimide film having a thickness of 75 μm. _{at, Ti x Al y N z (} x = 0.09, y = 0.43, z = 0.48) is formed by a thermistor film thickness 200nm of. The sputtering conditions at that time were an ultimate vacuum of 5 × 10 ⁻⁶ Pa, a sputtering gas pressure of 0.4 Pa, a target input power (output) of 200 W, and a nitrogen gas fraction of 20 in a mixed gas atmosphere of Ar gas + nitrogen gas. %.

A resist solution is applied onto the formed thermistor film by a spin coater, pre-baked at 110 ° C. for 1 minute 30 seconds, exposed to light with an exposure device, and unnecessary portions are removed with a developer, and further at 150 ° C. for 5 minutes. Patterning is performed by post-baking. Thereafter, wet etching thermistor film unnecessary Ti _x Al _y N _z in commercial Ti etchant, as shown in FIG. 2 (a), with a resist peeling in the thermistor layer 3 having a desired shape.

Next, a Cr layer having a thickness of 20 nm is formed on the thermistor film 3 by sputtering. Further, an Au layer having a thickness of 200 nm is formed on the Cr layer by sputtering.
Next, after applying a resist solution on the formed Au layer with a spin coater, pre-baking is performed at 110 ° C. for 1 minute 30 seconds, and after exposure with an exposure apparatus, unnecessary portions are removed with a developer, and at 150 ° C. Patterning is performed by post-baking for 5 minutes. Thereafter, unnecessary electrode portions are wet-etched in the order of commercially available Au etchant and Cr etchant, and as shown in FIG. 2B, a desired pair of comb electrodes 4A and 4B are formed by resist stripping.

Note that an insulating protective film may be formed by coating polyimide resin on the insulating base material 2 by screen printing so as to cover the pair of comb electrodes 4A and 4B and the thermistor film 3.
When a plurality of thin film thermistors are manufactured simultaneously, after forming the plurality of thermistor films 3 and the pair of comb-shaped electrodes 4A and 4B on the large sheet of the insulating base 2 as described above, each thin film thermistor 1 is formed from the large sheet. Disconnect.

  Next, in the resistance adjusting step, the resistance value between the pair of comb-shaped electrodes 4A and 4B is measured in advance, and when different from the predetermined resistance value, the base end portion or the other side base of at least one other comb tooth portion 5B. A trimming cutting part C is formed by irradiating a part of the end connection part 6B with YAG laser light and cutting the part. As a result, at least one other comb-tooth portion 5B is separated from the comb-shaped electrodes 4A and 4B, and the resistance value is adjusted, whereby the thin film thermistor 1 of the present embodiment is manufactured.

  As described above, in the thin film thermistor 1 and the manufacturing method thereof according to this embodiment, the one-side comb-tooth portion 5A is shorter than the other-side comb-tooth portion 5B, and the base end portion or the other side of at least one other-side comb-tooth portion 5B. Since a part of the base end connection portion 6B is cut with a laser beam to be a trimming cutting portion C, even if scattered matter scatters around at the time of cutting, as shown in FIG. The distance L1 between 5A and the other-side proximal end connecting portion 6B extends longer than the distance L2 between the other-side comb-tooth portion 5B and the one-side proximal end connecting portion 6A, thereby suppressing a short circuit between the electrodes. it can.

  Next, a second embodiment of the thin film thermistor and the method for manufacturing the same according to the present invention will be described below with reference to FIGS. Note that, in the following description of the embodiment, the same components described in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The difference between the second embodiment and the first embodiment is that, in the first embodiment, the base end portion of the other side comb tooth portion 5B and the other side base end connection portion 6B are formed on the thermistor film 3. On the other hand, in the thin film thermistors 21A and 21B of the second embodiment, as shown in FIGS. 3 and 4, the other-side base end connection portion 26B of the comb-shaped electrode 24B of the pair of comb-shaped electrodes 24A and 24B is replaced with the thermistor film 3. The trimming cutting part C is also arranged outside the thermistor film 3.

  That is, in the second embodiment, the base end portion of the other side comb tooth portion 25B, which becomes the trimming cutting portion C, and the other side base end connection portion 26B are lower than the thermistor film 3 in the drawings of FIGS. It shifts to the side and is detached from the thermistor film 3. Further, the tip of the one-side comb tooth portion 25 </ b> A connected to the one-side base end connection portion 26 </ b> A is arranged at the end side position of the thermistor film 3.

In FIG. 3, the thin film thermistor 21 </ b> A whose resistance value is adjusted is formed by cutting the base end portions of the other three comb-tooth portions 25 </ b> B on the right side in the drawing to form trimming cut portions C.
In FIG. 4, a thin film thermistor 21B whose resistance value is adjusted by cutting the other-side proximal end connecting portion 26B in the middle so as to cut off the three other-side comb-tooth portions 25B in the drawing to make a cutting portion C for trimming. It is said. Therefore, in the thin film thermistor 21B described in FIG. 4, the three other side comb-tooth portions 25B can be electrically disconnected by cutting only one place on the other side proximal end connecting portion 6B, and the total amount of scattered matter Can be reduced.

  As described above, in the thin film thermistors 21A and 21B and the manufacturing method thereof according to the second embodiment, the other-side base end connection portion 26B is arranged outside the thermistor film 3, and the trimming cutting portion C is also outside the thermistor film 3. Since the thermistor film 3 is not formed on the underlayer even when the laser trimming is performed, the material of the thermistor film 3 is not scattered and the short circuit can be further suppressed.

  The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

  1, 21A, 21B ... Thin film thermistor, 2 ... Insulating base material, 3 ... Thermistor film, 4A, 4B, 24A, 24B ... Comb electrode, 5A, 25A ... One side comb teeth, 5B, 25B ... Other side comb teeth Part, 6A, 26A ... one side proximal end connection part, 6B, 26B ... other side proximal end connection part, C ... trimming cutting part, L1 ... distance between one side comb tooth part and the other side proximal end connection part, L2 ... Distance between the other side comb teeth and one side proximal end connection

Claims (3)

An insulating substrate;
A thermistor film formed on the insulating substrate;
A pair of comb electrodes patterned on the thermistor film so as to face each other;
One of the pair of comb-shaped electrodes has a plurality of one-side comb teeth extending in the opposing direction, and a one-side proximal connection portion to which the base ends of the plurality of one-side comb teeth are connected. Have
The other of the pair of comb-shaped electrodes has a plurality of other side comb teeth extending in the opposing direction, and the other side proximal end connecting portion to which the base ends of the plurality of other side comb teeth are connected. Have
A plurality of the one-side comb teeth and a plurality of the other-side comb teeth are arranged alternately one by one,
The one-side comb-tooth portion is shorter than the other-side comb-tooth portion, and the distance between the one-side comb-tooth portion and the other-side proximal end connecting portion is such that the other-side comb-tooth portion and the one-side proximal end Set longer than the distance to the connection,
A thin film thermistor, wherein a base end portion of at least one other side comb tooth portion or a part of the other side base end connection portion is a cut portion for trimming. The thin film thermistor according to claim 1,
The other-side base end connecting portion is disposed outside the thermistor film;
The thin film thermistor, wherein the trimming cutting part is also arranged outside the thermistor film. A thin film forming step of forming a thermistor film on an insulating substrate;
A comb-shaped electrode forming step of forming a pair of comb-shaped electrodes facing each other on the thermistor film; and
A resistance adjustment step of adjusting a resistance value between the pair of comb electrodes,
One of the pair of comb-shaped electrodes has a plurality of one-side comb teeth extending in the opposing direction, and a one-side proximal connection portion to which the base ends of the plurality of one-side comb teeth are connected. Have
The other of the pair of comb-shaped electrodes has a plurality of other side comb teeth extending in the opposing direction, and the other side proximal end connecting portion to which the base ends of the plurality of other side comb teeth are connected. Have
A plurality of the one-side comb teeth and a plurality of the other-side comb teeth are arranged alternately one by one,
The one-side comb-tooth portion is shorter than the other-side comb-tooth portion, and the distance between the one-side comb-tooth portion and the other-side proximal end connecting portion is such that the other-side comb-tooth portion and the one-side proximal end Set longer than the distance to the connection,
In the resistance adjusting step, a base end portion of at least one other side comb tooth portion or a part of the other side base end connecting portion is cut with a laser beam.

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