JP2019027801A - Multifunctional integration sensor - Google Patents

Abstract

To provide a multifunctional integration sensor capable of obtaining a plurality of characteristic values and suppressing adhesion of a foreign matter to a diaphram while meeting downsizing requirements.SOLUTION: A multifunctional integration sensor comprises: a pressure sensor chip 20 cantilever-fixed to a first principal surface 10a in an end part of a lead frame 10 and including a diaphram 21b as a sensing part on one end side not fixed to the lead frame 10; a property sensor chip 30 cantilever-fixed to a second principal surface 10b in the end part of the lead frame 10 and in which a sensing part is formed on the one end side not fixed to the lead frame 10 and the one end side not fixed to the lead frame 10 is arranged facing the diaphram 21b of the pressure sensor chip 20; and a sealing resin body 40 sealing the lead frame 10, the pressure sensor chip 20, and the property sensor chip 30 so that the sensing parts of the pressure sensor chip 20 and the property sensor chip 30 are exposed to the outside.SELECTED DRAWING: Figure 1

Description

  The disclosure of this specification relates to a multifunction integrated sensor including a membrane-type pressure sensor.

  As described in Patent Document 1, a mold package in which one end side of a sensor chip is sealed with a mold resin and cantilevered with the mold resin is known.

JP 2013-16686 A

  By the way, for example, when controlling an internal combustion engine in a vehicle or the like, information on the pressure and temperature of a fluid such as oil is used. In addition to this, in recent years, more accurate control is required for the purpose of further improving fuel consumption and reducing the burden on the environment, and detection of properties such as the viscosity and the degree of deterioration of the fluid is being demanded.

  For example, pressure and temperature are important characteristic values in the control of an internal combustion engine. By configuring the pressure sensor as a wafer level package (WLP) as described in Patent Document 1, pressure and temperature can be detected, but properties such as viscosity depend on the estimated characteristic value, It is difficult to say that sufficient controllability is obtained with only a WLP pressure sensor.

  Therefore, it is conceivable to provide a property sensor for detecting properties such as viscosity at a location different from the pressure sensor, but at the present time when a smaller and lighter system is required, providing a new sensor separately, It goes against these requests.

  As another problem, particularly with respect to a diaphragm type pressure sensor, direct sensing is realized by being constituted by WLP, and good characteristics are obtained, while foreign matter adheres to the diaphragm exposed to the fluid, There is a possibility that the detected characteristic value varies.

  Therefore, an object of the disclosure of this specification is to provide a multi-function integrated sensor that can obtain a plurality of characteristic values while satisfying the demand for miniaturization, and can suppress adhesion of foreign matters to the diaphragm.

  The disclosure of this specification employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate a corresponding relationship with specific means described in the embodiments described later as one aspect, and limit the technical scope of the invention. Not what you want.

  In order to achieve the above object, the multifunction integrated sensor disclosed in this specification has a plate-like shape having a first main surface (10a) and a second main surface (10b) which is the back surface of the first main surface. A lead frame (10), a pressure sensor chip (20) having a diaphragm (21b) as a sensing part on one end side fixed to the first main surface at the end of the lead frame and not fixed to the lead frame; The end of the lead frame is cantilevered on the second main surface, the sensing part is formed on one end side that is not fixed to the lead frame, and the one end side that is not fixed to the lead frame is disposed opposite to the diaphragm of the pressure sensor chip. The lead frame, pressure sensor and the sensor chip (30) and the sensing parts of the pressure sensor chip and the property sensor chip are exposed to the outside. Comprising a sealing resin member for sealing the chip and property sensor chip (40), the.

  According to this, since the pressure sensor chip and the property sensor chip are integrally formed by the sealing resin body, the arrangement space can be saved as compared with an aspect in which each is arranged as a separate body. it can.

  Moreover, the diaphragm of the sensing part in a pressure sensor chip is arrange | positioned facing a property sensor chip. For this reason, before the foreign substance which exists in the medium which is a detection target adheres to a diaphragm, a course is obstructed by the property sensor chip. That is, entry of foreign matter into the diaphragm can be suppressed, and foreign matter can be prevented from adhering to the diaphragm or the vicinity thereof.

It is a three-plane figure which shows schematic structure of a multifunction integrated sensor. It is sectional drawing which shows the process of preparing a lead frame. It is sectional drawing which shows the process of mounting a pressure sensor chip. It is sectional drawing which shows the process of mounting a property sensor chip. It is sectional drawing which shows the process of wire bonding. It is sectional drawing which shows the process of installing a metal mold | die. It is sectional drawing which shows the process of inject | pouring a sealing resin body. It is sectional drawing which shows the process of removing a metal mold | die.

  Hereinafter, a plurality of modes for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly indicate that combinations are possible in each form, but also forms may be partially combined even if they are not clearly specified, as long as there is no problem with the combination. Is possible.

(First embodiment)
Initially, with reference to FIG. 1, schematic structure of the multifunction integrated sensor which concerns on this embodiment is demonstrated.

  The multifunction integrated sensor 100 is a sensor that is disposed in a flow path through which oil circulates among elements constituting an internal combustion engine in a vehicle, for example, and detects the pressure and temperature of the oil.

  As shown in FIG. 1, the multifunction integrated sensor 100 includes a lead frame 10, a pressure sensor chip 20, a property sensor chip 30, and a sealing resin body 40. In addition, illustration of the sealing resin body 40 is abbreviate | omitted in the top view in FIG.

  The lead frame 10 is a metal plate-like member, and becomes a substrate on which a control circuit chip and a chip capacitor (not shown) are mounted in addition to the pressure sensor chip 20 and the property sensor chip 30 described later. The lead frame 10 has a first main surface 10a and a second main surface 10b. At the outer edge of the lead frame 10, the pressure sensor chip 20 is fixed on the first main surface 10a side, and the property sensor chip 30 is on the surface opposite to the fixing surface of the pressure sensor chip 20 on the second main surface 10b side. It is fixed.

  The pressure sensor chip 20 is a diaphragm type pressure sensor. The pressure sensor chip 20 is formed by bonding a first semiconductor plate 21 and a second semiconductor plate 22 so as to be laminated. The first semiconductor plate 21 is a member to be joined to the lead frame 10, and the second semiconductor plate 22 is a side to which a bonding wire 29 described later is connected.

  A hole 21a is formed on the surface of the first semiconductor plate 21 on the side to be joined with the lead frame 10 so as not to penetrate in the thickness direction. The bottom of the hole 21a is a portion where the first semiconductor plate 21 is particularly thinned, and this portion becomes the diaphragm 21b. The diaphragm 21b is formed with, for example, a bridge-connected resistor, and the pressure and temperature of the fluid (oil) are detected based on the resistance value of each resistor that changes due to the displacement of the diaphragm 21b in the plate thickness direction. It is like that. As shown in FIG. 1, the diaphragm 21 a is formed at a position near the end of the first semiconductor plate 21. The diaphragm 21b is formed at a position that is not sealed by the sealing resin body 40, which will be described later, so that the diaphragm 21b can be in direct contact with the fluid, and so-called direct pressure sensing is possible. On the other hand, there is a possibility that foreign matter contained in the fluid enters and adheres to the hole 21a and hinders deformation of the diaphragm 21b. Note that one end of the first semiconductor plate 21 opposite to the position where the diaphragm 21 b is formed is joined to the lead frame 10 via an adhesive 28. A joint portion of the first semiconductor plate 21 with the lead frame 10 is sealed with a sealing resin body 40.

  A hole 22a that opens to the first semiconductor plate 21 side is formed in a portion of the second semiconductor plate 22 that corresponds to the diaphragm 21b. The hole 22a is joined to the first semiconductor plate 21 by the second semiconductor plate 22 and the opening is closed to form a sealed space. The diaphragm 21b separates this sealed space from the outside. The sealed space functions as a pressure reference chamber. That is, the diaphragm 21b is deformed based on the pressure difference between the reference pressure in the pressure reference chamber and the fluid (oil) existing outside, and the resistance value of the resistor constituting the bridge circuit changes. A bonding wire 29 is connected to one end of the second semiconductor plate 22 opposite to the position where the pressure reference chamber is formed. The bonding wire 29 electrically relays a control circuit chip (not shown) and the pressure sensor chip 20. Although not shown, a relay circuit that electrically connects the bridge circuit formed on the diaphragm 21 b and the bonding wire 29 is formed between the first semiconductor plate 21 and the second semiconductor plate 22. The bonding wire 29 electrically connects the relay circuit and the control circuit chip.

  As described above, the pressure sensor chip 20 is sealed with the sealing resin body 40 at the portion bonded and fixed to the lead frame 10, while the portion where the diaphragm 21 b is formed is outside the sealing resin body 40. It has a protruding cantilever structure.

  The property sensor chip 30 in the present embodiment is, for example, a tuning fork type vibration element. The tuning fork type vibration element is a vibrator made of a crystal body containing SiO2 as a main component, and an arm portion constituting the tuning fork vibrates by applying a predetermined voltage. The frequency changes according to the viscosity of the medium in contact with the arm. The tuning fork type vibration element can detect the viscosity and temperature of the medium based on the change in the frequency. The property sensor chip 30 includes a base 31 and an arm, and the arm includes a first vibrating arm 32 and a second vibrating arm 33.

  The base portion 31 is a support portion for the first vibrating arm 32 and the second vibrating arm 33 and has a circuit portion (not shown). The base 31 is bonded and fixed to the second main surface 10 b of the lead frame 10 via an adhesive 38. The formation position of the adhesive 38 is opposite to the adhesive 28 that fixes the pressure sensor chip 20 across the lead frame 10. The circuit portion formed on the base portion 31 is connected to the control circuit chip via bonding wires 39. The circuit unit receives the vibration voltage output from the control circuit chip and outputs information related to the viscosity related to the vibration of the arm unit to the control circuit chip. Most of the base portion 31 except the roots of the first vibrating arm 32 and the second vibrating arm 33 is sealed with the sealing resin body 40.

  The first vibrating arm 32 and the second vibrating arm 33 are formed to protrude from the base portion 31 in the same direction and in parallel. The protruding direction of the first vibrating arm 32 and the second vibrating arm 33 is the same as the protruding direction of the pressure sensor chip 20 from the sealing resin body 40. Further, the protruding lengths of the first vibrating arm 32 and the second vibrating arm 33 are substantially the same as the protruding length of the pressure sensor chip 20, and at least the first vibrating arm 32 and the second vibrating arm 33 form the diaphragm 21b. The length exceeds the position. The arrangement direction of the first vibrating arm 32 and the second vibrating arm 33 is a direction along a plane on which the diaphragm 21b is stretched. That is, the first vibrating arm 32 and the second vibrating arm 33 that are the sensing part of the property sensor chip 30 are disposed to face the diaphragm 21b that is the sensing part of the pressure sensor chip 20.

  The sealing resin body 40 is, for example, an epoxy resin, and seals the lead frame 10, a part of the pressure sensor chip 20, and a part of the property sensor chip 30 to protect them from the entry of foreign matter, vibration, impact, etc. doing. The sealing resin body 40 also seals a control circuit chip and a chip capacitor (not shown) disposed on the lead frame 10. In addition, a part of the connector that is connected to the control circuit chip and the chip capacitor and provided for external connection is also sealed, and the multi-function integrated sensor 100 has a pressure sensor chip from the sealing resin body 40 in appearance. 20 and a part of the property sensor chip 30 protrude, and a part of a connector for external connection is exposed as a module.

  Next, a method for manufacturing the multifunction integrated sensor 100 will be briefly described with reference to FIGS. 2 to 8 are shown as sectional views corresponding to the AA sectional view in FIG. Moreover, the pressure sensor chip 20 and the property sensor chip 30 are prepared through different processes, and are prepared in the multifunction integrated sensor 100.

  First, as shown in FIG. 2, a lead frame 10 is prepared. The lead frame 10 includes a main frame 11 and a sub frame 12. The main frame 11 and the sub frame 12 are connected at a portion (not shown) in the depth direction of the paper surface in FIG. 2, and are integrally formed at the time shown in FIG. This connecting portion is cut in a later process, and the main frame 11 and the subframe 12 are separated.

  Next, as shown in FIG. 3, the adhesive 28 is applied to the first main surface 10 a of the main frame 11, and the spacer 50 is disposed on the first main surface of the subframe 12. Then, the pressure sensor chip 20 is placed on the lead frame 10 via the adhesive 28 and the spacer 50 so as to bridge the main frame 11 and the subframe 12. As a result, one end of the pressure sensor chip 20 is fixed to the main frame 11 via the adhesive 28. On the other hand, one end of the pressure sensor chip 20 where the diaphragm 21 b is formed is supported by the subframe 12 via the spacer 50.

  Although not shown, a step of mounting a control circuit chip and a chip capacitor on the main frame 11 is performed before or after the step of placing the pressure sensor chip 20.

  Next, as shown in FIG. 4, the adhesive 38 is applied to the second main surface 10 b of the main frame 11, and the spacer 51 is disposed on the second main surface of the subframe 12. Then, the property sensor chip 30 is placed on the lead frame 10 via the adhesive 38 and the spacer 51 so as to bridge the main frame 11 and the subframe 12. Thereby, the base 31 of the property sensor chip 30 is fixed to the main frame 11 via the adhesive 38. On the other hand, the first vibrating arm 32 and the second vibrating arm 33 in the pressure sensor chip 20 are supported by the subframe 12 via the spacer 51.

  Next, as shown in FIG. 5, bonding wires 29 and 39 are connected. The bonding pressure sensor chip 20 and the control circuit chip are electrically connected by a bonding wire 29, and the property sensor chip 30 and the control circuit chip are electrically connected by a bonding wire 39.

  Next, as shown in FIG. 6, the connection of the bonding wires 29 and 39 is held between molds 60 and 61. The mold includes a first mold 60 and a second mold 61. The first mold 60 is a mold that sandwiches an object from the pressure sensor chip 20 side, and its inner wall surface is formed in a shape that follows the shape of the pressure sensor chip 20, the spacer 50, and the subframe 12. A first film 70 is attached to the inner wall surface of the first mold 60. The first film 70 is a member for interpolating a gap between the pressure sensor chip 20, the spacer 50, and the sub-frame 12 and the first mold 60 that is generated due to the intersection associated with the manufacture and assembly. The first mold 60 is formed such that there is no gap between the first mold 60 and the pressure sensor chip 20 at a portion overlapping the subframe 12.

  The 2nd metal mold | die 61 is a metal mold | die which pinches | interposes object from the property sensor chip 30 side, The inner wall surface is shape | molded in the shape along the shape of the property sensor chip 30, the spacer 51, and the sub-frame 12. FIG. A second film 71 is attached to the inner wall surface of the second mold 61. The 2nd film 71 is a member for interpolating the clearance gap between the 2nd metal mold | die 61 resulting from the crossing which concerns on manufacture and an assembly | attachment of the property sensor chip 30, the spacer 51, and the sub-frame 12. As shown in FIG. The 2nd metal mold | die 61 is shape | molded so that a clearance gap may not be formed between the property sensor chips 30 in the part which overlaps with the sub-frame 12. FIG.

  Next, as shown in FIG. 7, the semi-liquid sealing resin body 40 is injected into the space formed by the molds 60 and 61. As a result, the main frame 11 is buried in the sealing resin body 40, and one end side of the pressure sensor chip 20 and the property sensor chip 30 that are bonded and fixed to the main frame 11 is sealed by the sealing resin body 40. Further, the bonding wires 29 and 39, the control circuit chip, the chip capacitor, and a part of the connector are also sealed.

  Next, as shown in FIG. 8, the molds 60 and 61 and the films 70 and 71 are removed. As a result, the pressure sensor chip 20 and the property sensor chip 30 are cantilevered by the sealing resin body 40 with the spacers 50 and 51 and the subframe 12 interposed therebetween.

  Thereafter, the lead frame 10 is die-cut to separate the main frame 11 and the subframe 12. Then, by removing the separated subframe 12 and the spacers 50 and 51 temporarily fixed to the subframe 12, the multifunction integrated sensor 100 shown in FIG. 1 can be manufactured.

  Next, the effect by employ | adopting the multifunction integrated sensor 100 which concerns on this embodiment is demonstrated.

  The multifunction integrated sensor 100 can detect the pressure of the fluid by the pressure sensor chip 20 and can detect the viscosity of the fluid by the tuning fork type vibration element as the property sensor chip 30. Since these sensor chips 20 and 30 are integrally formed by the sealing resin body 40 and the control system can be shared by the control circuit chip, it is possible to contribute to space saving when arranging the sensor chips. .

  Further, since the property sensor chip 30 is disposed opposite to the diaphragm 21b which is a sensing part in the pressure sensor chip 20, the property sensor chip 30 becomes an obstacle to a foreign substance moving in the fluid toward the diaphragm 21b. Further, it is possible to prevent foreign matter from adhering to the diaphragm 21b.

  In particular, the property sensor chip 30 in the present embodiment is a tuning fork type vibration element, and the portions facing the diaphragm 21 b are the first vibrating arm 32 and the second vibrating arm 33. These arm portions 32 and 33 intentionally vibrate when energized, and the main purpose is to detect the viscosity of the fluid. In addition to this effect, the vibrating arm portions 32 and 33 prevent foreign matters floating in the fluid from staying in the vicinity of the diaphragm 21b. That is, it is possible to reduce the probability that foreign matter adheres to the diaphragm 21b.

  Furthermore, since the property sensor chip 30 includes the first vibrating arm 32 and the second vibrating arm 33, there is an effect of stirring the fluid around the arm portions 32 and 33. For example, a fluid having a high viscosity at a low temperature or the like may pass without contacting the diaphragm 21b in the course of flowing, but the first vibrating arm 32 and the second vibrating arm 33 are fluidized by vibration. Can be stirred and brought into contact with the diaphragm 21b.

  Further, by the fluid agitation by the first vibrating arm 32 and the second vibrating arm 33, the temperature unevenness of the fluid around the multifunction integrated sensor 100 can be made more uniform. That is, the temperature responsiveness can be improved in the temperature detection by the pressure sensor chip 20 or the property sensor chip 30. In particular, when detecting the temperature at an extremely low temperature, the temperature of the property sensor chip 30 should be detected in consideration of the fact that the viscosity of the fluid is relatively high and the fluid is difficult to contact the diaphragm 21b. Is preferred.

(Other embodiments)
The preferred embodiment has been described above, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist disclosed in this specification.

  In the above-described embodiment, an example in which a tuning fork type vibration element is employed as the property sensor chip 30 has been described, but another property detection chip may be employed. For example, a surface acoustic wave element (SAW element) for stress detection may be employed. Also in this aspect, by arranging the SAW element so as to face the diaphragm 21b in the pressure sensor chip 20, adhesion of foreign matters to the diaphragm 21b can be suppressed. However, in order to obtain a stirring effect by vibration, it is preferable to employ a tuning fork type vibration element.

  By the way, when the pressure is detected by the pressure sensor chip 20, a change in resistance value due to temperature may be corrected to improve pressure detection accuracy. In the diaphragm type pressure sensor chip 20, there is a possibility that an error occurs in the correction value due to heat transfer from the sealing resin body 40. On the other hand, if a tuning fork type vibration element is used for the property sensor chip 30, the vibration of the arm portions 32 and 33 can reduce the influence of heat transfer compared to the temperature detection by the resistance value by the pressure sensor chip 20. . For this reason, when the pressure is detected, the temperature of the fluid detected by the property sensor chip 30 is used for correcting the pressure, so that the pressure can be corrected with higher accuracy than when the pressure sensor chip alone corrects the temperature. It can be carried out. The property object is, for example, gas and liquid.

DESCRIPTION OF SYMBOLS 10 ... Lead frame, 20 ... Pressure sensor chip, 21b ... Diaphragm, 30 ... Property sensor chip, 32 ... 1st vibration arm, 33 ... 2nd vibration arm, 40 ... Sealing resin body

Claims (3)

A plate-like lead frame (10) having a first main surface (10a) and a second main surface (10b) which is the back surface of the first main surface;
A pressure sensor chip (20) having a diaphragm (21b) as a sensing portion on one end side that is cantilevered and fixed to the first main surface at the end of the lead frame and not fixed to the lead frame;
A sensing portion is formed at one end of the lead frame that is cantilevered to the second main surface, not fixed to the lead frame, and one end that is not fixed to the lead frame faces the diaphragm of the pressure sensor chip. A property sensor chip (30) arranged in a
A multifunctional device comprising: the lead frame, and a sealing resin body (40) for sealing the pressure sensor chip and the property sensor chip so that a sensing portion of the pressure sensor chip and the property sensor chip is exposed to the outside. Integrated sensor. The property sensor chip is a tuning fork type vibration element having a base portion (31) and an arm portion, and the arm portion includes a first vibrating arm (32) extending from the base portion and the first vibration from the base portion. A second vibrating arm (33) extending parallel to the arm,
2. The multi-piece according to claim 1, wherein the base is fixed to the second main surface, and a surface in which the first vibrating arm and the second vibrating arm are arranged in the arm portion faces the diaphragm of the pressure sensor chip. Function integrated sensor.   The temperature of the medium in contact with the arm estimated based on a temperature characteristic of vibration of the arm of the tuning fork type vibration element is used for correcting the pressure detected by the pressure sensor chip. Multifunctional integrated sensor.

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