JP2012068149A - Electrostatic capacitance type pressure sensor, pressure measuring device and method for manufacturing electrostatic capacitance type pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic capacitance type pressure sensor capable of detecting not only a pressure but also a temperature.SOLUTION: The electrostatic capacitance type pressure sensor 100 includes: a substrate 1 having a first electrode portion 4 formed thereon; a second electrode portion 7 formed on the surface of the substrate 1 through an insulator layer 2; a diaphragm 10 which is partially connected to the second electrode portion 7 through a bonding layer 8 formed by intermetallic bonding, and is deformed depending on a pressure; and a temperature sensor 22 which is formed on the surface of the insulator layer 2, and is composed of a material containing at least platinum.

Description

  The present invention relates to a capacitive pressure sensor having a diaphragm portion that deforms in accordance with pressure, a method for manufacturing the same, and a pressure measuring device using the capacitive pressure sensor.

  Conventionally, as represented by Patent Document 1 below, a capacitive pressure sensor having a diaphragm portion that deforms according to pressure has been publicly known. The capacitive pressure sensor disclosed in Patent Document 1 includes a first substrate on which an electrode portion is formed, and a second substrate on which a diaphragm portion that is deformed according to pressure is formed. Provided with a cavity part in which the diaphragm part and the electrode part face each other with a gap, and a sensor chip joined to the first and second substrates, The gap width of the gap is changed according to the pressure difference between the pressure to be measured and the pressure in the cavity portion, and the capacitance between the diaphragm portion and the electrode portion changes due to the change in the gap width. The capacitance-type pressure sensor configured to detect the pressure difference includes a sealing member that seals the inside of the cavity.

Japanese Patent Laid-Open No. 10-19709

  The capacitance-type pressure sensor disclosed in Patent Document 1 is capable of detecting pressure, but recently, a sensor capable of detecting other physical quantities such as temperature with a single sensor is desired.

  Therefore, an object of the present invention is to provide a capacitive pressure sensor that can detect not only pressure but also temperature.

(1) A capacitive pressure sensor according to the present invention includes a substrate on which a first electrode portion is formed, a second electrode portion formed on the surface of the substrate via an insulator layer, a metal A material including at least platinum formed on the surface of the diaphragm portion, a diaphragm portion that is partially connected to the second electrode portion via a bonding layer formed by inter-bonding and deforms in response to pressure The temperature sensor part which consists of.

  According to the configuration of (1) above, a capacitive pressure sensor that can detect not only pressure but also temperature can be obtained.

(2) In the capacitance type pressure sensor of (1), between the first electrode portion and the substrate, between the second electrode portion and the bonding layer, and the bonding layer, It is preferable that a barrier metal layer containing at least platinum is formed between the diaphragm portion. Here, the barrier metal is (1) capable of forming a dense film and having a barrier effect against the reaction between the wiring material and the silicon substrate, and (2) excellent adhesion to the metal and the insulating film. This refers to a material such as a metal having advantageous effects such as (3) fine processing by dry etching and (4) low electrical resistance.

  According to the configuration of (2) above, the effect of the barrier metal described above can be enjoyed.

(3) In the capacitance type pressure sensor of the above (1) or (2), it is preferable that the bonding layer is formed by gold-gold bonding.

  According to the configuration of (3) above, electrical connection reliability can be improved. Particularly in the capacitance type pressure sensor of the above (2), when the bonding layer is formed by gold-gold bonding, the effect of the barrier metal layer can be enjoyed, so that the connection reliability is higher. And can.

(4) The capacitance according to any one of claims 1 to 3, wherein the pressure measuring device of the present invention has a sealed space inside, and the diaphragm portion forms a part of the sealed space. A die pressure sensor, a substrate on which a third electrode portion is formed, a fourth electrode portion formed on the surface of the substrate via an insulator layer, and a through hole are provided. Partly connected to the fourth electrode part through the formed bonding layer, another diaphragm part deformed according to pressure, and a material including at least platinum formed on the surface of the insulator layer And a space formed so as to communicate with the outside through the through-hole, with the other diaphragm portion as a lid member, and formed in parallel with the capacitive pressure sensor. With other capacitive pressure sensors, Eteiru. The pressure measuring device of the present invention detects a pressure value from the difference between the capacitance change of the capacitance type pressure sensor and the capacitance change of the other capacitance type pressure sensor.

  With configuration (4) above, it is possible to detect a pressure value such as atmospheric pressure more accurately and easily.

(5) The manufacturing method of the present invention is the manufacturing method of the capacitance-type pressure sensor according to (2), wherein a step of forming an insulator layer on a substrate and processing the insulator layer into a predetermined shape Forming a layer made of a material containing at least platinum on the insulator layer after the processing, forming the layer made of a material containing at least platinum into a predetermined shape, and forming the temperature sensor unit, the first And simultaneously forming a barrier metal layer between one electrode portion and the substrate, and a barrier metal layer between the second electrode portion and the bonding layer and the insulator layer. It is what.

  According to the configuration of (5) above, the temperature sensor portion on the insulator layer, the barrier metal layer between the first electrode portion and the substrate, the second electrode portion and the bonding layer, and the insulator layer A barrier metal layer between them can be formed at the same time. Therefore, the capacitance type pressure sensor (2) can be easily manufactured.

It is the schematic of the capacitive pressure sensor which concerns on 1st Embodiment of this invention, Comprising: (a) is a top view, (b) is AA sectional drawing of (a). It is a figure which shows each manufacturing process of the electrostatic capacitance type pressure sensor shown in FIG. It is the schematic of the pressure measuring device which concerns on 2nd Embodiment of this invention, Comprising: (a) is a top view, (b) is BB sectional drawing of (a).

<First Embodiment>
Hereinafter, the capacitive pressure sensor according to the first embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1A and 1B, a capacitive pressure sensor 100 includes a substrate 1, an insulator layer 2, a barrier metal layer 3, a first electrode portion 4, and a barrier metal layer. 5, barrier metal layer 6, second electrode portion 7, bonding layer 8, barrier metal layer 9, diaphragm portion 10, temperature sensor electrode portions 20 and 21, and temperature sensor portion 22. It is what it has.

  The substrate 1 is made of a semiconductor such as silicon, and has a circular recess 1a in a substantially central portion.

  The insulator layer 2 is a layer made of an insulator such as silicon dioxide, and is formed on the substrate 1. Further, the insulator layer 2 includes a circular penetrating portion 2a formed at a substantially central portion in accordance with the concave portion 1a of the substrate 1, and a substantially rectangular penetrating portion 2b as shown in FIG. It is what you have.

  The barrier metal layer 3 is made of a material containing at least platinum (platinum, platinum / titanium, etc.), and is formed on the substrate 1 and inside the through portion 2b.

  The first electrode portion 4 is made of a metal material such as gold, silver, or copper, and is formed on the barrier metal layer 3.

  The barrier metal layers 5 and 6 are made of a material containing at least platinum (platinum, platinum / titanium, etc.). Further, the barrier metal layer 5 is formed on the insulator layer 2 so as to have a ring shape having an inner ring portion that matches the shape of the through portion 2a. The barrier metal layer 6 is integrally formed with the barrier metal layer 5 together with the wiring connecting the barrier metal layer 5 and the barrier metal layer 6.

  The second electrode portion 7 is made of a metal material such as gold, silver, or copper, and is formed on the barrier metal layer 6.

  The bonding layer 8 is formed by bonding a metal layer 8a made of a metal material such as gold, silver, or copper and a metal layer 8b. The metal layer 8a is formed on the barrier metal layer 5 so as to have a ring shape having an inner ring portion that matches the shape of the penetrating portion 2a. Similarly, the metal layer 8b is formed on the metal layer 8a so as to have a ring shape having an inner ring portion that matches the shape of the penetrating portion 2a. Here, the metal layer 8 a is integrally formed with the second electrode portion 7 together with the wiring 12 connecting the metal layer 8 a and the second electrode portion 7.

  The barrier metal layer 9 is made of a material containing at least platinum (platinum, platinum / titanium, etc.), and has a ring shape having an inner ring portion that matches the shape of the through portion 2a on the metal layer 8b. It is formed as follows.

  The diaphragm portion 10 is made of a semiconductor material such as silicon and can be deformed according to pressure. The diaphragm portion 10 is a circular lid member that closes one end portion of the bonding layer 8. Is forming.

  The temperature sensor electrode portions 20 and 21 are provided on the insulator layer 2 so as to face each other with the diaphragm portion 10 and the like interposed therebetween, and are connected to the temperature sensor portion 22 via wiring.

  The temperature sensor unit 22 is made of a material containing at least platinum (platinum, platinum / titanium, etc.), and is formed in a semicircular shape along the outer edge of the barrier metal layer 5 on the insulator layer 2. Is. Here, as a modification, the shape of the temperature sensor unit 22 does not have to be semicircular, and may be any shape as long as it can be formed on the insulator layer 2.

  Next, an example of a method for manufacturing the capacitive pressure sensor 100 will be described with reference to FIG. 2A and 2B, the right end portion (portion corresponding to the right end portion in FIG. 1B) is partially omitted, and there is a portion that does not correspond to FIG. 1B. I refuse. Hereinafter, an example of a manufacturing method of the capacitive pressure sensor 100 will be described.

  First, the surface of a plate-like material made of silicon (for example, a silicon wafer) is thermally oxidized to form insulator layers 13 and 14 made of silicon dioxide on both surfaces of the substrate 1 (see FIG. 2A). Next, the insulator layer 13 is etched to form the insulator layer 2 having the through portions 2a and 2b (see FIG. 2B).

  Subsequently, the barrier metal layers 3, 5, 6 and the precursor layer 15 of the temperature sensor unit 22, the first electrode unit 4, the metal layer 8a, and the second electrode unit are formed by sputtering from the insulator layer 2 side. 7 precursor layers 16 are laminated in the order of the precursor layers 15 and 16 (see FIG. 2C). Then, the predetermined part of the precursor layer 16 is etched, and the 1st electrode part 4, the metal layer 8a, and the 2nd electrode part 7 are formed (refer FIG.2 (d)).

  Subsequently, a predetermined portion of the precursor layer 15 is etched to form the barrier metal layers 3, 5, 6 and the temperature sensor unit 22 (see FIG. 2E). Thereafter, the concave portion 1a is formed from the upper surface side of the substrate 1 by RIE (Reactive Ion Etching) (see FIG. 2F).

  Next, the precursor layer 19 and the barrier metal layer of the diaphragm portion 10 are formed on the insulator layer 20 by sputtering using a substrate 24 made of an SOI wafer having the insulator layer 20 different from the substrate 1 described above. 9 precursor layers 18 and a precursor layer 17 of the metal layer 8b are sequentially stacked. (See FIG. 2 (g)).

  Subsequently, the precursor layers 17 and 18 are etched so as to have a predetermined shape, thereby forming the barrier metal layer 9 and the metal layer 8b (see FIG. 2H). Thereafter, the precursor layer 19 is etched to form the diaphragm portion 10 (see FIG. 2 (i)).

  Subsequently, the element shown in FIG. 2 (i) is inverted and merged with the element shown in FIG. 2 (f), and the metal layer 8b in the element shown in FIG. The metal layer 8a in the element shown is joined. Here, as a modification, the element shown in FIG. 2 (f) is inverted and combined with the element shown in FIG. 2 (i), and the metal layer 8b in the element shown in FIG. The metal layer 8a in the element shown in 2 (f) may be bonded.

  Subsequently, the substrate 24 is removed by etching (see FIG. 2 (k)). Finally, the insulating layer 20 and the insulating layer 14 are removed by etching to obtain the capacitive pressure sensor 100. (See FIG. 2 (l)).

  Next, the operation of the capacitive pressure sensor 100 will be described. When pressure due to atmospheric pressure is applied from the diaphragm portion 10 side of the capacitive pressure sensor 100, the diaphragm portion 10 deforms according to the pressure. A change in capacitance between the diaphragm unit 10 and the first electrode unit 4 and the second electrode unit 7 caused by the deformation is detected, and the pressure is measured. At the same time, the temperature is measured by the temperature sensor unit 22.

  According to the above configuration, the capacitive pressure sensor 100 can detect not only the pressure but also the temperature.

  In addition, since the barrier metal layer is provided, (1) a dense film can be formed and has a barrier effect against the reaction between the wiring material and the silicon substrate, and (2) the metal and the insulating film. The capacitive pressure sensor 100 having the advantageous effects of the barrier metal layer, such as one having excellent adhesiveness, (3) fine processing by dry etching, and (4) low electrical resistance, can be obtained.

  Further, for example, when the bonding layer 8 is formed by gold-gold bonding, electrical connection reliability can be improved. In particular, when the bonding layer 8 is formed by gold-gold bonding, the effect of the above-described barrier metal layer can be enjoyed, so that higher connection reliability can be obtained.

  Further, the temperature sensor part 22 on the insulator layer 2, the barrier metal layer 3 between the first electrode part 4 and the substrate 1, and the second electrode part 7, the bonding layer 8 and the insulator layer 2. The barrier metal layers 5 and 6 therebetween can be formed simultaneously. Therefore, the capacitive pressure sensor 100 can be easily manufactured.

Second Embodiment
Next, a pressure measuring device according to a second embodiment of the present invention will be described with reference to FIG. In addition, since the site | parts 1-12 of 1st Embodiment and the site | parts 201-212 (there are some parts which are not illustrated) of this embodiment are the same in order, description may be abbreviate | omitted. Similarly, since the parts 1 to 9 and 12 of the first embodiment and the parts 301 to 309 and 312 of the present embodiment are the same in order, the description may be omitted.

  The pressure measuring apparatus 1000 according to the present embodiment is formed in parallel with the capacitance type pressure sensor 200 similar to that of the first embodiment and the capacitance type pressure sensor 200, and only the diaphragm unit 310 is different from the first embodiment. The electrostatic capacity type pressure sensor 300 is provided.

  The diaphragm portion 310 has a through hole 310 a that allows the inside of the internal space 311 to communicate with the outside. The diaphragm part 310 can be formed together with the diaphragm part 210 in the capacitive pressure sensor 200 by etching similar to the diaphragm part 10 of the first embodiment. Note that the through-hole 310a can be formed by using a mask having a through-hole at a predetermined position during the etching.

  Next, the operation of the pressure measuring apparatus 1000 will be described. When a pressure due to atmospheric pressure is applied from the diaphragm part 210 side of the capacitive pressure sensor 200, the diaphragm part 210 deforms in accordance with the pressure. A change in capacitance between the diaphragm unit 210 and the first electrode unit 204 and the second electrode unit 207 caused by the deformation is detected. At this time, since the diaphragm portion 310 in the capacitive pressure sensor 300 has the through hole 310a, it is not deformed by the pressure due to the atmospheric pressure. Therefore, there is no capacitance change between the diaphragm portion 310 and the first electrode portion 304 and the second electrode portion 307. The difference between the capacitance change of the capacitive pressure sensor 200 detected in this way and the capacitance change (zero) of the capacitance pressure sensor 300 is acquired, and the pressure value is detected from the difference. By acquiring the difference, the parasitic capacitance of the capacitive pressure sensor 200 can be canceled by the parasitic capacitance of the capacitive pressure sensor 300, so that the pressure value can be detected more accurately. . Simultaneously with these operations, the temperature is measured by the temperature sensor units 222 and 322.

  According to the pressure measuring apparatus 1000 of this embodiment, a pressure value such as atmospheric pressure can be detected more accurately and easily.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible based on the meaning of this invention, and these are not excluded from the scope of the present invention. For example, in the second embodiment, integrated substrates may be used for the capacitive pressure sensors 200 and 300.

  In the second embodiment, each of the insulator layer, the barrier metal layer, the metal layer (substrate side), the first electrode unit, and the second electrode unit in the capacitive pressure sensors 200 and 300 is as follows. Each precursor layer may be stacked in each manufacturing process and then etched into a predetermined shape to form the precursor layer. Thereby, the site | part similar to each site | part in 2nd Embodiment can be formed simultaneously, Therefore The pressure measuring apparatus 1000 can be manufactured more easily.

1a, 301a Recesses 1, 24, 301 Substrate 2, 13, 14, 20, 202, 302 Insulator layer 2a, 2b, 202b, 302a, 302b Through-hole 3, 5, 6, 9, 303, 305, 306, 309 Barrier metal layers 4, 204, 304 First electrode portion 7, 207, 307 Second electrode portion 8, 308 Bonding layers 8a, 8b, 308a, 308b Metal layers 10, 210, 310 Diaphragm portion 11 Sealed spaces 12, 212 , 312 Wiring 15, 16, 17, 18, 19 Precursor layer 20, 21 Temperature sensor electrodes 22, 222, 322 Temperature sensor 100, 200, 300 Capacitive pressure sensor 310a Through hole 311 Internal space 1000 Pressure measuring device

Claims (5)

A substrate on which a first electrode portion is formed;
A second electrode portion formed on the surface of the substrate via an insulator layer;
A diaphragm part that is partially connected to the second electrode part via a bonding layer formed by metal-to-metal bonding and deforms according to pressure,
And a temperature sensor portion made of a material containing at least platinum and formed on the surface of the insulator layer.   Between the first electrode portion and the substrate, between the insulator layer and the bonding layer, between the insulator layer and the second electrode portion, and between the bonding layer and the diaphragm portion; A capacitance type pressure sensor according to claim 1, wherein a barrier metal layer containing at least platinum is formed between them.   3. The capacitive pressure sensor according to claim 1, wherein the bonding layer is formed by gold-gold bonding. The capacitive pressure sensor according to any one of claims 1 to 3, wherein the capacitive pressure sensor has a sealed space inside, and the diaphragm portion forms a part of the sealed space;
A substrate on which a third electrode portion is formed, a fourth electrode portion formed on the surface of the substrate via an insulator layer, and a bonding layer provided with a through hole and formed by intermetal bonding Another diaphragm part that is partly connected to the fourth electrode part via the pipe and deforms according to pressure, and a temperature sensor part that is formed on the surface of the insulator layer and is made of a material containing at least platinum. The other diaphragm portion as a lid member, and a space formed so as to communicate with the outside via the through hole, and another electrostatic capacitance formed in parallel with the capacitive pressure sensor A capacitive pressure sensor, and
A pressure measuring device that detects a pressure value from a difference between a capacitance change of the capacitance type pressure sensor and a capacitance change of the other capacitance type pressure sensor. It is a manufacturing method of the capacitance type pressure sensor according to claim 2,
Forming an insulator layer on the substrate;
Processing the insulator layer into a predetermined shape;
Forming a layer made of a material containing at least platinum on the insulator layer after the processing;
The layer made of a material containing at least platinum is formed in a predetermined shape, and the temperature sensor part, a barrier metal layer between the first electrode part and the substrate, the second electrode part and the insulator layer, And a step of simultaneously forming a barrier metal layer between the bonding layer and the insulator layer, and a method of manufacturing a capacitive pressure sensor, comprising: .

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