JP2009058230A - Manufacturing method for sensor device, and the sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a sensor device and a sensor device capable of suppressing damage to a thin portion and variations in sensor characteristics, while ensuring an electrically connected state between a sensor chip and an external connection lead. <P>SOLUTION: A sensor chip in which a detection part and a wiring part connected to the detection part are formed on a substrate, having a cavity and a resistor composing the detection part, is formed on a thin portion above the cavity, and a lead frame including a support lead and an external connection lead are prepared. After a laminate is formed by fixing the prepared sensor chip on the support lead via an adhesive member, the external connection lead is electrically connected to the wiring part. The laminate and a stopper, having hardness closer to that of the substrate than that of the adhesive member; are disposed in the cavity configured in a pair of molds, and molding is performed with the stopper being held in between the two molds, while the one of the molds is in contact with the top surface of the sensor chip. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides a sensor chip in which a sensor chip in which a resistor of a detection part is formed on a thin part on a hollow part is disposed on a support lead, and an electrical connection site is molded while exposing the thin part and the detection part. The present invention relates to a device manufacturing method and a sensor device.

  Conventionally, for example, as shown in Patent Document 1, a thin-walled portion has a sensor chip in which a resistor of a detection unit is formed in a thin-walled portion on a hollow portion, and the sensor chip is disposed on a support lead. In addition, a sensor device molded so that the detection unit is exposed is known.

In the thermal air flow sensor disclosed in Patent Document 1, in a semiconductor sensor element (sensor chip), a heating resistor constituting a flow rate detection unit is formed on a diaphragm (thin wall portion) on a cavity formed in a semiconductor substrate. ing. Then, the semiconductor sensor element is arranged on the closing support lead (support lead) with the lower surface of the semiconductor substrate (the back surface of the heating resistor forming surface) as a contact surface, so that the flow rate detector and the diaphragm are exposed. The respective connecting portions are integrally covered with a molding material.
Japanese Patent No. 3328547

  The sensor device disclosed in Patent Document 1 employs a support lead provided with positioning portions corresponding to three side surfaces of a semiconductor substrate by bending, and a sensor chip is disposed on the support lead. In such a configuration, in consideration of mountability, the positioning portion is formed with a slight margin with respect to the semiconductor substrate, and thus there is a possibility that the sensor chip may be displaced. In addition, since the sensor chip is not fixed to the support lead, when the sensor chip and the external connection lead are wire-bonded using ultrasonic waves, there is a problem that ultrasonic vibration escapes and it is difficult to form a bonded state. is there.

  In view of this, the present inventor examined a structure in which the entire lower surface of the sensor chip (semiconductor substrate) is bonded and fixed (die bonded) to the support lead with the entire lower surface as an adhesive surface. However, when a soft adhesive member (one that is deformed by pressurization, Young's modulus is about 1 MPa) is used as the adhesive member (die bond material), the thin-walled portion is damaged (eg, broken) during molding. Occurred. It is considered that this is caused by the stress generated in the sensor chip due to the influence of the adhesive member being spread during molding, and the stress being concentrated on the thin portion.

  Further, when an adhesive member that is harder than the above-described adhesive member (that is difficult to be deformed by pressurization) is used, there is a problem that the sensor characteristics fluctuate. The fluctuation of the sensor characteristics is more remarkable as the Young's modulus is larger (those that hardly deform by pressurization, for example, about 1 GPa). This is because, for example, a stress based on a difference in linear expansion coefficient between the semiconductor substrate and the support lead occurs due to a curing process of the adhesive member or a temperature change in the usage environment, and the stress acts on a thin portion with low rigidity in the semiconductor substrate. This is thought to be because the resistance value changed due to the piezoresistance effect. Moreover, it is considered that the changed resistance value gradually changed due to creep.

  In view of the above problems, the present invention provides a method for manufacturing a sensor device and a sensor device capable of suppressing damage to a thin portion and fluctuation in sensor characteristics while securing an electrical connection state between a sensor chip and an external connection lead. For the purpose.

  In order to achieve the above object, according to the first aspect of the present invention, a detection part and a wiring part connected to the detection part are formed on a substrate having a cavity part, and the resistor constituting the detection part is provided on the cavity part. A preparatory step for preparing a sensor chip formed on the thin-walled portion, a lead frame including a support lead for mounting the sensor chip on one surface and an external connection lead electrically connected to the wiring portion, and the prepared sensor The chip is fixed to the support lead in the lead frame with an adhesive member using the lower surface where the cavity is open as a mounting surface, and an adhesion process for forming a laminate, and external connection leads in the lead frame to the laminate A connecting step for electrically connecting the wiring portion, and after the connecting step, the laminate is placed in a cavity formed in a pair of molds and molded, and a sealing member is used while exposing the detection portion and the thin portion. And a molding process for covering a connection portion between the wiring portion and the external connection lead, and in the molding process, a stopper having a hardness closer to the substrate than the adhesive member is formed in the cavity. The molding is characterized in that one mold is in contact with the upper surface of the sensor chip and the stopper is sandwiched between the other mold and the mold.

  Thus, according to the present invention, the external connection lead and the wiring portion of the sensor chip are electrically connected in a state where the sensor chip is fixed to the support lead via the adhesive member. Therefore, an electrical connection state can be ensured between the sensor chip and the external connection lead.

  In addition, a stopper having a hardness closer to the substrate than that of the adhesive member is disposed in the cavity, and molding is performed with one mold contacting the upper surface of the sensor chip and holding the stopper between the other mold. To do. Therefore, the stopper can further prevent the sensor chip from being pressed from the state where one mold is in contact with the upper surface of the sensor chip. In other words, the pressure received from the mold can be dispersed by the stopper and the sensor chip. As a result, even if a soft adhesive member having a Young's modulus (for example, about 1 MPa) that deforms under pressure is used, the deformation amount of the adhesive member during mold clamping is reduced, and as a result, the adhesive member deforms as the adhesive member deforms. The amount of deformation of the sensor chip can be reduced. And the stress concentration on the thin portion can be suppressed (damage to the thin portion can be suppressed).

  Moreover, since the damage which a thin part receives with a stopper can be suppressed, the soft adhesive member which receives a pressure and deform | transforms as an adhesive member is employable. Therefore, even if a stress is generated based on a difference in linear expansion coefficient between the substrate constituting the sensor chip and the support lead due to a temperature change in the usage environment, the stress can be reduced (relaxed) by the soft adhesive member. That is, it is possible to reduce the stress acting on the thin portion of the sensor chip based on the difference in coefficient of linear expansion, and to suppress fluctuations in sensor characteristics due to the piezoresistance effect.

  In the invention described in claim 1, as described in claim 2, a fixing step of fixing a stopper on one surface of the support lead may be provided before the molding step. As described above, when the stopper as the separate member is fixed to the support lead, the sensor chip and the stopper are fixed to the same support lead, so that the positional accuracy of the stopper with respect to the upper surface of the sensor chip can be improved. That is, the variation in pressure of the sensor chip received from the mold can be reduced. Further, since the stopper is positioned and fixed with respect to the sensor chip before the molding step, a structure for positioning and fixing the stopper at the time of molding is unnecessary, and the mold structure can be simplified.

  Further, as described in claim 3, in the preparation step, a convex stopper protruding from one surface may be formed as a part of the support lead. As described above, when the stopper is formed as a part of the support lead, the positional accuracy of the stopper which is a part of the support lead with respect to the upper surface of the sensor chip fixed to the support lead can be further improved. That is, the variation in pressure of the sensor chip received from the mold can be further reduced. Further, the fixing step required in the invention of claim 2 can be eliminated. Further, the mold structure can be simplified as in the second aspect of the invention.

  Next, in the invention described in claim 4, a detection unit and a wiring unit connected to the detection unit are formed on a substrate having a cavity, and the resistor constituting the detection unit is a thin-walled part on the cavity. A preparatory process for preparing the sensor chip formed on the lead frame including a support lead for mounting the sensor chip on one surface and an external connection lead electrically connected to the wiring portion; and the prepared sensor chip, The lower surface where the cavity is opened is used as the mounting surface, and is fixed to the support lead in the lead frame via an adhesive member, and the bonding process for forming the laminate, and the external connection leads and the wiring portion in the lead frame are connected to the laminate. A connecting step for electrical connection, and after the connecting step, the laminate is placed in a cavity formed in a pair of molds and molded, and the wiring portion is formed by the sealing member while exposing the detection portion and the thin portion. A sensor device comprising: a molding step for covering a connection portion with the part connection lead, wherein the mold on the upper surface side of the sensor chip is the upper surface of the sensor chip as at least one mold in the molding step. When the contact is made, a mold is used in which a convex stopper is formed which is in direct contact with the opposite part of the other mold or via a support lead.

  Thus, also in the present invention, the external connection lead and the wiring portion of the sensor chip are electrically connected in a state where the sensor chip is fixed to the support lead via the adhesive member. Therefore, an electrical connection state can be ensured between the sensor chip and the external connection lead.

  In addition, a mold having a convex stopper is used as at least one of the pair of molds. This stopper is configured so that when the mold on the upper surface side of the sensor chip comes into contact with the upper surface of the sensor chip at the time of mold clamping, the stopper directly contacts the opposite portion of the other mold or indirectly through the support lead. Is formed. Therefore, the stopper can further suppress the pressing of the sensor chip from the state in which the mold on the upper surface side of the sensor chip is in contact with the upper surface of the sensor chip. In other words, the pressure received from the mold can be dispersed by the stopper and the sensor chip. As a result, even if a soft adhesive member having a Young's modulus (for example, about 1 MPa) that deforms under pressure is used, the deformation amount of the adhesive member during mold clamping is reduced, and as a result, the adhesive member deforms as the adhesive member deforms. The amount of deformation of the sensor chip can be reduced. And the stress concentration on the thin portion can be suppressed (damage to the thin portion can be suppressed).

  Moreover, since the damage which a thin part receives with a stopper can be suppressed, the soft adhesive member which receives a pressure and deform | transforms as an adhesive member is employable. Therefore, even if a stress is generated based on a difference in linear expansion coefficient between the substrate constituting the sensor chip and the support lead due to a temperature change in the usage environment, the stress can be reduced (relaxed) by the soft adhesive member. That is, it is possible to reduce the stress acting on the thin portion of the sensor chip based on the difference in coefficient of linear expansion, and to suppress fluctuations in sensor characteristics due to the piezoresistance effect.

  The invention according to any one of claims 1 to 4 is configured such that a flow rate detection chip including a flow rate detection unit including a heater formed on a thin portion as a detection unit is a sensor chip. Especially effective.

  The thickness of the thin portion in the flow rate detection chip is preferably as thin as possible in order to improve the response of the heater, and is generally about several μm. Therefore, the thin-walled portion is easily damaged during molding, and the sensor characteristics are likely to fluctuate due to the piezoresistance effect. On the other hand, if the invention according to any one of claims 1 to 4 is applied, the damage received by the thin-walled portion and fluctuations in sensor characteristics are ensured while ensuring the electrical connection state between the flow rate detection chip and the external connection lead. A suppressed flow sensor device can be formed.

  Next, in the invention described in claim 6, the detection part and the wiring part connected to the detection part are formed on the substrate having the cavity part, and the resistor constituting the detection part is formed in the thin part on the cavity part. The formed sensor chip, a part of the lead frame, and a support lead in which the sensor chip is fixed on one surface with an open lower surface of the cavity portion via an adhesive member, and the wiring portion and the An externally connected external connection lead, and a sealing member made of an insulating material and integrally disposed so as to cover the connection portion between the wiring portion and the external connection lead while exposing the detection portion and the thin portion A stopper having a hardness closer to the substrate than the adhesive member is formed on one surface of the support lead and excluding the sensor chip mounting region. It is characterized by.

  Thus, according to the present invention, the sensor chip is bonded and fixed to the support lead. Thereby, the position shift of the sensor chip is suppressed, and the electrical connection state between the sensor chip and the external connection lead is ensured.

  A stopper having a hardness closer to the substrate than the adhesive member is formed on one surface of the support lead in an area excluding the sensor chip mounting area. Thereby, the pressure which a sensor chip receives from a metal mold | die at the time of shaping | molding by sealing resin is suppressed. In other words, the pressure received from the mold is distributed between the stopper and the sensor chip. Therefore, even if a soft adhesive member having a Young's modulus (for example, about 1 MPa) that deforms under pressure is used as the adhesive member, the amount of deformation of the adhesive member at the time of clamping is reduced. The amount of deformation of the sensor chip that deforms accordingly is reduced. Then, the concentration of stress on the thin portion is suppressed (damage to the thin portion is suppressed).

  A stopper is formed on the support lead. Thereby, the positional accuracy of the stopper with respect to the upper surface of the sensor chip fixed on the support lead is improved, and the variation in the pressure of the sensor chip received from the mold is reduced.

  Moreover, since the damage which a thin part receives by a stopper is suppressed, the soft adhesive member which receives a pressure and deform | transforms as an adhesive member is employable. Therefore, even if a stress is generated based on a difference in linear expansion coefficient between the substrate constituting the sensor chip and the support lead due to a temperature change in the usage environment, the stress is reduced (relaxed) by the soft adhesive member. That is, the stress acting on the thin portion of the sensor chip based on the difference in coefficient of linear expansion is reduced, and as a result, fluctuations in sensor characteristics due to the piezoresistance effect are suppressed.

  In the invention described in claim 6, as described in claim 7, a stopper, which is a member different from the support lead, may be fixed on one surface of the support lead. Thus, the first convex portion formed as a part of the support lead may be used as a stopper. The operational effects of the inventions according to the seventh and eighth aspects are the same as the operational effects of the inventions according to the second and third aspects, respectively, so that description thereof is omitted.

  In the invention according to any one of claims 6 to 8, as described in claim 9, the stopper may be formed on one surface of the support lead and in the vicinity of the sensor chip mounting region. preferable. With such a configuration, the positional accuracy of the stopper with respect to the upper surface of the sensor chip fixed on the support lead is further improved.

  In the invention described in claim 9, as described in claim 10, it is preferable that the back surface of the stopper facing the support lead is substantially flush with the upper surface of the sensor chip. With such a configuration, the structure of the mold used at the time of molding with the sealing resin is simplified, and the positional accuracy of the stopper with respect to the upper surface of the sensor chip fixed on the support lead is further improved. Further, when the sensor chip is a flow rate detection chip, the occurrence of turbulent flow by the stopper is suppressed, and the flow rate detection accuracy is improved.

  In the invention according to any one of claims 6 to 10, as described in claim 11, the stopper is preferably formed in an annular shape so as to surround the sensor chip. Thus, when it is set as the structure by which the stopper was formed around the sensor chip, the pressure which a sensor chip receives from a metal mold | die at the time of shaping | molding is suppressed without partial deviation.

  In the invention described in claim 11, as described in claim 12, the annular stopper is formed away from the sensor chip, and is a region not covered by the sealing member in the gap between the stopper and the sensor chip. A configuration may be adopted in which at least a part of the region from the boundary with the sealing member is filled with a filling member different from the sealing member or a second protrusion formed as a part of the support lead.

  With such a configuration, the flow of the sealing member into a region that is not covered by the sealing member in the gap between the stopper and the sensor chip during molding is suppressed. As a result, the range of stress generated based on the difference in linear expansion coefficient between the sensor chip and the stopper is limited due to a temperature change in the use environment. That is, fluctuations in sensor characteristics due to the piezoresistance effect are suppressed.

  According to a thirteenth aspect of the present invention, the annular stopper may be configured to be in contact with the sensor chip in a region that is not covered by the sealing member and is at least a part of the region from the boundary with the sealing member. As described above, even in a configuration in which a portion that contacts the sensor chip is formed in a part of the stopper, the same effect as that of the invention described in claim 12 can be expected.

  In the invention described in any one of claims 6 to 13, as described in claim 14, the sensor chip may be directly fixed to the support lead via an adhesive member. Even in such a configuration, damage to the thin portion and fluctuations in sensor characteristics are suppressed by the effect of the stopper described above.

  Further, as described in claim 15, a part of the stopper is disposed between one surface of the support lead and the lower surface of the sensor chip so as to face a part of the lower surface of the sensor chip, and a part of the lower surface of the sensor chip. Further, a configuration may be adopted in which the opposing portion of the stopper is fixed via a first adhesive member as an adhesive member, and the sensor chip is fixed to the support lead via the stopper.

  With such a configuration, even when a soft adhesive member that deforms under pressure is used as the adhesive member (first adhesive member), the adhesive member is pressed between the stopper and the sensor chip by receiving pressure during mold clamping. The range in which the sensor chip is pulled by is limited to the portion opposite the stopper (a part of the lower surface of the sensor chip). Thereby, compared with the structure where the sensor chip is directly bonded and fixed to the support lead, damage to the thin portion is further suppressed.

  Further, since only a part of the lower surface of the sensor chip is brought into contact with the adhesive member, stress generated based on the difference in linear expansion coefficient is reduced as compared with a configuration in which the entire lower surface is in contact with the adhesive member.

  In the fifteenth aspect of the present invention, as described in the sixteenth aspect, at least a part of the region excluding the opposing region of the stopper on the lower surface of the sensor chip and the support lead are harder than the first adhesive member. It is good also as a structure fixed through the adhesive member.

  Thus, when the range of the lower surface of the sensor chip supported on the support lead is wide, the durability of the sensor chip against external force (including pressure during molding) is improved.

  The invention according to any one of claims 6 to 16 has a configuration in which a flow rate detection chip including a flow rate detection unit including a heater formed on a thin portion as a detection unit is used as a sensor chip. Especially effective. Since the effect of the invention described in claim 17 is the same as that of the invention described in claim 5, the description is omitted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a thermal flow sensor will be described as an example of the sensor device.
(First embodiment)
FIG. 1 is a top view plan view showing a schematic configuration of the thermal flow sensor according to the present embodiment. 2 is a cross-sectional view taken along line II-II in FIG. 3 is a cross-sectional view taken along line III-III in FIG. The white arrow shown in FIG. 1 indicates the fluid flow direction (normal time). The thermal flow sensor shown in the present embodiment is disposed, for example, in an intake pipe of a vehicle internal combustion engine.

  The thermal flow sensor 100 shown in FIGS. 1 to 3 includes a flow rate detection chip 10 that is exposed to air as a fluid to be measured and detects the flow rate as a main part, and a part of a lead frame. The support lead 31 that supports the flow rate detection chip 10, the external connection lead 32 that is configured as a part of the lead frame and electrically connects the flow rate detection chip 10 and the outside, and the stopper formed on the support lead 31 50 and a sealing member 70 that covers a connection portion between the flow rate detection chip 10 and the external connection lead 32.

  The flow rate detection chip 10 includes a thin portion (membrane) 13 formed of a thin insulating layer formed on the cavity portion 12 by forming the cavity portion 12 by etching in the semiconductor substrate 11 made of single crystal silicon. And a heater 14 formed in the thin portion 13. As described above, when the semiconductor substrate 11 is used as the substrate, the thin portion 13 can be easily formed by etching from the back side of the thin portion 13, and the heater 14 can detect the flow rate with high sensitivity as will be described later. It can function as a part.

  Here, the flow rate detection chip 10 will be described in more detail with reference to FIGS. 4 and 5. FIG. 4 is a plan view showing a schematic configuration of the flow rate detection chip. FIG. 5 is a cross-sectional view taken along line VV in FIG. In FIG. 4, for the sake of convenience, the heater, the temperature sensor, and the interlayer insulating film and protective film on the connecting wiring are omitted. Moreover, the white arrow shown in FIG. 4 has shown the flow direction (normal time) of the fluid.

  As shown in FIGS. 4 and 5, a cavity 12 is formed in the semiconductor substrate 11 corresponding to the pair of heaters 14 (14 a, 14 b) constituting the flow rate detection unit. The cavity 12 is formed on the back surface of the contact surface of the semiconductor substrate 11 with the insulating layer 15 (hereinafter, referred to as the lower surface of the semiconductor substrate 11) on the rectangular opening 16 (of the rectangular broken line shown in FIG. 4). The area of the opening is reduced toward the upper surface side (contact surface side with the insulating layer 15) of the semiconductor substrate 11, and is smaller than the opening 16 on the upper surface of the semiconductor substrate 11. In the direction perpendicular to the thickness direction of the semiconductor substrate 11, a rectangular bottom surface portion 17 (a region inside the rectangular broken line shown in FIG. 4) included in the opening 16 is formed.

  In the present embodiment, a silicon oxide film is employed as the insulating layer 15, and a part of the insulating layer 15 constitutes the bottom surface portion 17 of the cavity portion 12 described above. Thus, in the flow rate detection chip 10, the portion corresponding to the bottom surface portion 17 is a thin portion 13 (membrane). Heaters 14 a and 14 b are formed in the thin portion 13. The thin portion 13 is formed thinner than other portions constituting the flow rate detecting portion (for example, about several μm), thereby suppressing the heat capacity to be low and thermally insulating from other portions. Is secured.

  On the insulating layer 15 constituting the bottom surface portion 17 (thin wall portion 13), heaters 14a and 14b are formed. The heater 14a is an upstream heater disposed on the upstream side in the fluid flow direction, and the heater 14b is a downstream heater disposed on the downstream side in the fluid flow direction. A pair of temperature sensing elements 18a and 18b made of resistance temperature detectors are sandwiched between the pair of heaters 14a and 14b, respectively, in the thin part peripheral region thicker than the thin part 13 and upstream and downstream of the fluid, respectively. Is formed. The temperature detectors 18a and 18b constitute a flow rate detection unit together with the heaters 14a and 14b. The heaters 14 a and 14 b and the temperature sensing elements 18 a and 18 b are connected to a pad 20 to which a wire 91 is connected via a connecting wire 19. The connecting wiring 19 corresponds to the wiring portion described in the claims.

  Then, an interlayer insulating film 21 made of, for example, a silicon oxide film is laminated so as to cover these heaters 14 a, 14 b, temperature sensing elements 18 a, 18 b, and connecting wires 19, and the interlayer insulating film 21 is made of, for example, a silicon nitride film A protective film 22 is laminated.

  In the flow rate detection chip 10 configured as described above, the heaters 14a and 14b have a function of sensing their own temperature based on a change in their own resistance values in addition to the function of generating heat according to the amount of current supplied. Have. Then, the flow rate of the fluid is detected based on the heat deprived by the fluid among the heat generated in the heaters 14a and 14b on the upstream side and the downstream side. In addition, the flow direction of the fluid is detected based on the difference in the amount of heat taken away by the fluid among the heat generated in the upstream heater 14a and the downstream heater 14b. Further, based on the temperature difference between the upstream heater 14a and the upstream temperature sensor 18a and the temperature difference between the downstream heater 14b and the downstream temperature sensor 18b, the temperature is supplied to the heaters 14a and 14b. The amount of current is controlled. For details of such a flow rate detection chip 10, refer to, for example, Japanese Patent Application Laid-Open Nos. 2004-205498 and 2004-241398 by the present applicant.

  The support lead 31 supports the flow rate detection chip 10 and is configured as a part of a lead frame made of a metal material together with the external connection lead 32. That is, the support lead 31 is configured using a material different from the semiconductor substrate 11 constituting the flow rate detection chip 10 (for example, a material having a linear expansion coefficient different from that of single crystal silicon such as 42 alloy or Cu). Thus, if the support lead 31 is configured as a part of the lead frame, the configuration of the thermal flow sensor 100 can be simplified. In the present embodiment, the support lead 31 has a planar rectangular shape as shown by a broken line in FIG. 1, and its size is larger than that of the flow rate detection chip 10, and the flow rate detection chip 10 has a lower surface (flow rate detection portion forming surface). , A plane surrounding the opening 16 of the cavity 12) is disposed so as to be completely opposed to the support lead 31. The flow rate detection chip 10 is fixed on the support lead 31 via the adhesive member 90, and the cavity 12 of the flow rate detection chip 10 is blocked by the opening 16 by the support lead 31. Thereby, since the cavity part 12 is not directly exposed to the air which is a fluid to be measured, noise due to turbulent flow can be reduced.

  Here, the adhesive member 90 is a so-called die bond material, and the constituent material and form thereof are not particularly limited as long as the flow rate detection chip 10 can be bonded and fixed to the support lead 31. Only an organic component may be used, or an organic component mixed with an inorganic component or a metal component (for example, an Ag paste) may be used. In the present embodiment, as the adhesive member 90, a soft adhesive member having a Young's modulus (for example, about 1 MPa) that is deformed by receiving pressure in a cured state is employed. Specifically, an adhesive member 90 that has been formed into a film (sheet) in a state before the curing process is adopted, and the adhesive member is applied to the entire facing region between the lower surface of the flow rate detection chip 10 and one surface (upper surface) of the support lead 31. 90 is arranged. That is, on the lower surface of the flow rate detection chip 10, the adhesive member 90 is also disposed around the cavity 12 (opening 16), and is also disposed in a region corresponding to the pad 20 that is a connection portion with the wire 91. ing.

  The external connection lead 32 electrically connects the flow rate detection chip 10 and the outside, and is configured as a part of a lead frame made of a metal material together with the support lead 31. In this embodiment, the wire 91 made of, for example, Au is connected to the external connection lead 32 and the pad 20 of the flow rate detection chip 10 by a joining method using ultrasonic waves, and the external connection lead 32 and the flow rate detection chip are connected. 10 are electrically connected.

  The stopper 50 is a member for reducing the pressure received by the flow rate detection chip 10 from the mold during molding, and is disposed in a cavity formed in a pair of molds and is sandwiched between the molds. It is formed using a material that does not deform. As such a material, a material having a hardness closer to that of the semiconductor substrate 11 (for example, about Young's modulus of about 180 MPa) than an adhesive member 90 (for example, about Young's modulus of about 1 MPa) that deforms under pressure can be adopted. In the present embodiment, the stopper 50 is formed using the same material as the lead frame (support lead 31) (for example, Young's modulus of about 100 MPa to 200 MPa), and joined to the upper surface of the support lead 31 to It is integrated.

  Further, the form of the stopper 50 is not particularly limited as long as it fulfills the above-described function. In the present embodiment, as shown in FIGS. 2 and 3, the stopper 50 is opposed to the upper surface of the support lead 31 in a state of being joined to the region other than the mounting region of the flow rate detection chip 10 on the upper surface of the support lead 31. The back surface (upper surface) of the surface is substantially flush with the upper surface of the flow rate detection chip 10. Moreover, as shown in FIGS. 1-3, it is formed in the cyclic | annular form corresponding to the shape (plane rectangular shape) of the flow volume detection chip 10 so that the flow volume detection chip 10 may be surrounded in the vicinity. That is, the stopper 50 is not in contact with the flow rate detection chip 10, and a slight gap is formed between the stopper 50 and the flow rate detection chip 10.

  The sealing member 70 covers the connection portion between the flow rate detection chip 10 and the external connection lead 32 while exposing the flow rate detection portion and the thin portion 13 of the flow rate detection chip 10, and is integrally molded (molded) with epoxy resin or the like It is configured using an electrically insulating material that can be molded). In the present embodiment, the sealing member 70 integrally covers the connection portion of the wire 91, the wire 91 and the flow rate detection chip 10 (pad 20), and the connection portion of the wire 91 and the external connection lead 32. Yes.

  In the present embodiment, the sealing member 70 excludes not only the pad-side end portion 71 that covers each of the connection portions described above, but also the end surface of the flow rate detection chip 10 on the end portion side where the pad 20 is formed. A peripheral portion 72 formed so as to surround the remaining three end surfaces (side surfaces of the semiconductor substrate 11) is integrated with the pad-side end portion 71. The peripheral portion 72 is formed on the outer peripheral side of the stopper 50 in the direction away from the flow rate detection chip 10 so as to cover the end portion of the support lead 31, and the flow rate detection chip on the upper surface of the support lead 31. The end on the 10 side is in contact with the back surface of the stopper 50 facing the flow rate detection chip 10. The upper surface 72a of the peripheral portion 72 is substantially flush with the upper surface of the stopper 50 (the upper surface of the flow rate detection chip 10). That is, in the fluid flow direction, the upper surface 72a of the peripheral portion 72, the upper surface of the stopper 50, and the upper surface of the flow rate detection chip 10 are flush with each other, whereby the fluid is more rectified on the flow rate detection unit. It becomes. In other words, by the end surface 71a on the flow rate detection unit side at the pad side end portion 71 disposed on the flow rate detection chip 10, the upper surface 72a of the peripheral portion 72, and the upper surface of the stopper 50 (and the upper surface of the flow rate detection chip 10). A flow path for the flow rate detection unit is configured.

  Further, in the present embodiment, as shown in FIGS. 1 and 3, a region that is not covered with the sealing member 70 in the gap formed between the stopper 50 and the flow rate detection chip 10 on the support lead 31. In addition, the filling member 92 is disposed in at least a part of the region from the boundary with the pad-side end portion 71 to close the gap. The filling member 92 functions to prevent the sealing member 70 from leaking into the gap on the flow rate detection unit side from the pad side end portion 71 side at the time of molding. For example, a resin material is used. Can do. In the present embodiment, as shown in FIG. 1, they are arranged in a part of the region including the boundary with the pad side end portion 71.

  Next, a manufacturing method of the thermal flow sensor 100 configured as described above will be described with reference to FIGS. 6A and 6B are cross-sectional views showing a method for manufacturing the thermal flow sensor 100, wherein FIG. 6A is a state after the bonding process is finished, FIG. 6B is a state after the connection process is finished, and FIG. FIG. 6A to 6C correspond to FIG.

  First, a lead frame 30 having a flow rate detection chip 10, a support lead 31, and an external connection lead 32 is prepared. Then, the flow rate detection chip 10 is bonded and fixed to the support lead 31 which is a part of the lead frame 30 with the lower surface where the cavity 12 is opened as the bonding surface. In this adhesive fixing, the adhesive member 90 may be disposed on the upper surface of the support lead 31, or the adhesive member 90 may be disposed on the lower surface of the flow rate detection chip 10. In the present embodiment, as shown in FIG. 6A, a film-like (sheet-like) adhesive member 90 is disposed on the upper surface of the support lead 31. Then, the flow rate detection chip 10 is disposed on the adhesive member 90 so that the lower surface thereof is in contact with the adhesive member 90 disposed on the support lead 31, and the adhesive member 90 is cured in this state. Thereby, the flow rate detection chip 10 is fixed to the support lead 31 via the adhesive member 90, and a laminated body in which the flow rate detection chip 10 is stacked on the support lead 31 is formed. That is, the cavity 12 in the flow rate detection chip 10 is closed by the support lead 31.

  After bonding, the annular stopper 50 is fixed (bonded) to the upper surface of the support lead 31 so as to surround the flow rate detection chip 10. In this joined state, the upper surface of the stopper 50 and the upper surface of the flow rate detection chip 10 are substantially flush. Although not shown, in the present embodiment, after the stopper 50 is joined, in order to suppress the flow of the sealing member 70 into the gap in a part of the gap between the stopper 50 and the flow rate detection chip 10, A filling member 92 (see FIGS. 1 and 3) is disposed.

  Next, as shown in FIG. 6B, the pad 20 (see FIGS. 1 and 4) of the flow rate detection chip 10 and the external connection lead 32 are electrically connected by wire bonding. In the present embodiment, the wire 91 made of Au is connected to the external connection lead 32 and the pad 20 of the flow rate detection chip 10 using a bonding method using ultrasonic waves. Here, when joining using ultrasonic waves, if the flow rate detection chip 10 is not fixed, the flow rate detection chip 10 is free, so that ultrasonic vibrations escape and a good joined state cannot be formed. However, in this embodiment, since wire bonding is performed in a state where the flow rate detection chip 10 is bonded and fixed to the support lead 31, a good bonding state can be formed. Further, since the wire bonding is performed in a state where the region corresponding to the pad formation region on the lower surface of the flow rate detection chip 10 and the upper surface of the support lead 31 facing the region are bonded and fixed, a better bonding state is formed. be able to. As a result, as shown in FIG. 6B, the flow rate detection chip 10 (pad 20) and the external connection lead 32 are electrically connected via the wire 91.

  Next, the laminated body after wire bonding is placed in the cavities formed in the molds 93 and 94, and in a state where the molds are clamped, the molten sealing member is injected into the cavities and integrally molded. As a result, as shown in FIG. 6C, the flow rate detection unit including the thin portion 13 is exposed in the laminate, and the wire 91, the connection part of the wire 91 and the flow rate detection chip 10 (pad 20), and the wire 91 are exposed. And the connection part between the external connection lead 32 and the sealing member 70 are integrally covered.

  Specifically, as shown in FIG. 6C, a portion 93 a in contact with the upper surface of the flow rate detection chip 10 and a portion 93 b in contact with the upper surface of the stopper 50 among the cavity constituting surfaces of the upper mold 93 in contact with the upper surface of the flow rate detection chip 10. The upper mold 93 is configured so that they are substantially flush with each other. Accordingly, the cavity structure surface of the upper mold 93 is held in a state where the laminate is sandwiched between the cavity structure surface parts 93a and 93b of the upper mold 93 and the cavity structure surface part 94a of the lower mold 94 (clamping state). A part 93 a that is a part contacts the upper surface of the flow rate detection chip 10, and a part 93 b that is a part of the cavity constituting surface contacts the upper surface of the stopper 50. Further, a concave portion 93c is formed in a portion between the two portions 93a and 93b and facing the thin portion 13 so that the upper mold 93 does not contact the thin portion 13 even in a clamped state. It has become.

  In the present embodiment, a part of the gap between the stopper 50 on the support lead 31 and the flow rate detection chip 10 including a portion that becomes a boundary with the pad-side end 71 in the sealing member 70. By disposing the filling member 92, a part of the gap is closed. Therefore, the sealing member 70 does not flow into the portion on the flow rate detection unit side of the filling member 92 in the gap.

  In this embodiment, the support lead 31 and the external connection lead 32 are configured as a part of the lead frame 30. Therefore, the mutual positional accuracy including the flow rate detection chip 10 can be improved. Further, the wire bonding process and the molding process can be simplified.

  After the molding process, unnecessary portions of the lead frame 30 are removed through curing of the sealing member 70. As a result, the support lead 31 and the external connection lead 32 are electrically separated. And the thermal type flow sensor 100 shown in FIGS. 1-3 is formed.

  Next, the effect of the thermal flow sensor 100 configured as described above will be described.

  In the configuration in which the flow rate detection chip 10 is disposed on the support lead 31, a soft adhesive member (one that deforms due to pressure after curing, for example, Young's modulus) is used as an adhesive member for fixing the flow rate detection chip 10 to the support lead 31. Is about 1 MPa), the thin-walled portion 13 is damaged by the pressure when the mold is clamped, and may be damaged in some cases. This is because the adhesive member after curing is spread between the flow rate detection chip 10 and the support lead 31 at the time of molding, and the flow rate detection chip 10 adjacent to the adhesion member is pulled along with the deformation of the adhesive member, thereby causing the semiconductor substrate 11 to be pulled. This is considered to be caused by the stress generated on the thin-walled portion 13 having low rigidity.

  On the other hand, in the present embodiment, the stopper 50 having a hardness that does not deform even when sandwiched between the molds 93 and 94 is disposed in a cavity constituted by the molds 93 and 94, and the upper mold 93 has a flow rate. Injection molding is performed in a state where the stopper 50 is held between the lower die 94 and the upper surface of the detection chip 10. Therefore, the stopper 50 can suppress further pressing the flow rate detection chip 10 toward the lower mold 94 from the state in which the upper mold 93 is in contact with the upper surface of the flow rate detection chip 10. In other words, the pressure received from the molds 93 and 94 can be dispersed by the stopper 50 and the flow rate detection chip 10. As a result, even when a soft adhesive member 90 having a Young's modulus (for example, about 1 MPa) that deforms under pressure is used, the deformation amount of the adhesive member 90 during mold clamping is reduced, and as a result, the adhesive member 90 is deformed. The amount of deformation of the flow rate detection chip 10 that deforms accordingly can be reduced. Then, stress concentration on the thin portion 13 can be suppressed (damage to the thin portion 13 is suppressed).

  In the case where the flow rate detection chip 10 is arranged on the support lead 31, the semiconductor substrate 11 and the support lead 31 constituting the flow rate detection chip 10 have different linear expansion coefficients. A stress based on the difference in linear expansion coefficient is generated. When such stress acts on the thin-walled portion 13 with low rigidity, the resistance value changes due to the piezoresistance effect, and the sensor characteristics vary with respect to the target value. Further, when the stress is gradually relieved by creep, the resistance value changes and the sensor characteristics fluctuate. In particular, since the surrounding area of the cavity portion 12 has a short distance from the thin portion 13, the stress based on the difference in the expansion coefficient generated in the surrounding region of the cavity portion 12 has a great influence on the fluctuation of the thin portion 13 and thus the sensor characteristics. Become.

  On the other hand, in this embodiment, since the damage received by the thin portion 13 can be suppressed by the stopper 50, a soft adhesive member that deforms under pressure can be employed as the adhesive member 90. Therefore, even if stress is generated based on a difference in linear expansion coefficient between the semiconductor substrate 11 constituting the flow rate detection chip 10 and the support lead 31 due to a temperature change in the use environment, the stress is reduced (relaxed) by the soft adhesive member 90. )can do. That is, it is possible to reduce the stress acting on the thin portion 13 of the flow rate detection chip 10 based on the difference in linear expansion coefficient, and to suppress fluctuations in sensor characteristics due to the piezoresistance effect.

  Thus, according to the manufacturing method according to the present embodiment, the electrical connection state between the flow rate detection chip 10 and the external connection lead 32 is ensured, and damage to the thin portion 13 and fluctuations in sensor characteristics are suppressed. Can do. Further, the thermal flow sensor 100 formed by using this manufacturing method ensures an electrical connection state between the flow rate detection chip 10 and the external connection lead 32, and damage to the thin portion 13 and fluctuations in sensor characteristics are prevented. The sensor device is suppressed.

  In the present embodiment, the flow rate detection chip 10 and the stopper 50 are fixed to the same support lead 31. Therefore, the positional accuracy of the upper surface of the stopper 50 with respect to the upper surface of the flow rate detection chip 10 can be improved. That is, the pressure variation of the flow rate detection chip 10 received from the molds 93 and 94 can be reduced. Further, since the stopper 50 is positioned and fixed with respect to the flow rate detection chip 10 before the molding process, a structure for positioning and fixing the stopper 50 at a predetermined position in the cavity is not required at the time of molding, and the mold structure is simplified. be able to.

  In the present embodiment, the stopper 50 is formed in the vicinity of the mounting area of the flow rate detection chip 10 on the upper surface of the support lead 31. Therefore, the positional accuracy of the upper surface of the stopper 50 with respect to the upper surface of the flow rate detection chip 10 fixed on the support lead 31 can be further improved.

  In the present embodiment, the upper surface of the stopper 50 is substantially flush with the upper surface of the flow rate detection chip 10. Therefore, the structure of the mold 93 on the side in contact with the upper surface of the flow rate detection chip 10 can be simplified. Thereby, the positional accuracy of the upper surface of the stopper 50 with respect to the upper surface of the flow rate detection chip 10 can be further improved. Further, in the formed thermal flow sensor 100, the occurrence of turbulent flow by the stopper 50 is suppressed, and the flow rate detection accuracy is improved.

  In the present embodiment, the shape of the stopper 50 is an annular shape surrounding the flow rate detection chip 10. Therefore, the pressure received by the flow rate detection chip 10 from the molds 93 and 94 during molding can be reduced without partial deviation. Further, since the stopper 50 is only one member, it is easy to position and fix on the support lead 31.

  In the present embodiment, the filling member 92 is disposed in at least a part of the gap between the annular stopper 50 and the flow rate detection chip 10 from the boundary with the pad-side end portion 71. Therefore, the filling member 92 can suppress the sealing member 70 from flowing into a region not covered with the sealing member 70 in the gap. Then, by limiting the range of the sealing member 70 disposed in the gap, based on the linear expansion coefficient difference between the semiconductor substrate 11 constituting the flow rate detection chip 10 and the stopper 50 due to a temperature change or the like in the use environment. The range of generated stress can be limited. That is, fluctuations in sensor characteristics due to the piezoresistance effect can be suppressed.

  Note that the structure for preventing the sealing member 70 from flowing into a region not covered by the sealing member 70 in the gap is not limited to the arrangement of the filling member 92. In addition to this, for example, as shown in FIG. 7, at least a boundary between the annular stopper 50 and the flow rate detection chip 10 and at least the pad-side end portion 71 by the convex portion 31 a protruding from the upper surface of the support lead 31. It is also possible to have a structure in which a part of the region is filled (closed). Such convex portions 31a can be formed by etching or the like. Further, as shown in FIG. 8, a convex portion 50 a is formed on a part of the stopper 50, and at least the pad-side end portion 71 in the gap between the annular stopper 50 and the flow rate detection chip 10 is formed by the convex portion 50 a. A structure may be adopted in which a partial region from the boundary is filled (closed). 7 and 8 are cross-sectional views showing modifications, and correspond to FIG.

  Further, in the present embodiment, an example in which the upper surface of the stopper 50 is substantially flush with the upper surface of the flow rate detection chip 10 before being molded is shown. However, in the state before molding, as shown in FIG. 9A, the stopper 50 is supported by the support lead 31 so that the upper surface of the stopper 50 is slightly lower than the upper surface of the flow rate detection chip 10 with respect to the upper surface of the support lead 31. You may fix to the upper surface of 31. In this case, at the time of molding, as shown in FIG. 9 (b), a portion 93a corresponding to the flow rate detection chip 10 is part of the part 93a, 93b of the cavity constituting surface of the upper mold 93 that is substantially flush with each other. First, the top surface of the flow rate detection chip 10 is contacted. Then, in a state where the flow rate detection chip 10 is pushed to the support lead 31 side to some extent while deforming the adhesive member 90, the portion 93 b corresponding to the stopper 50 comes into contact with the upper surface of the stopper 50, and the stopper 50 is attached to the molds 93 and 94. It becomes a pinched state between them. Therefore, positional variations between the upper surface of the flow rate detection chip 10 and the upper surface of the stopper 50 can be reduced. Thereby, in the thermal flow sensor 100, generation | occurrence | production of the turbulent flow by the stopper 50 can be suppressed. FIG. 9 is a cross-sectional view showing a modified example of the manufacturing method, in which (a) shows the molding process and (b) shows the molding process. In addition, it is preferable that the difference between the upper surface of the flow rate detection chip 10 and the upper surface of the stopper 50 in a state before molding is set to such an extent that the thin portion 13 is not damaged at least during molding.

  In the present embodiment, the example in which the stopper 50 is fixed to the upper surface of the support lead 31 after the flow rate detection chip 10 is fixed to the support lead 31 is shown. However, the stopper 50 may be fixed to the support lead 31 before the molding process. For example, it may be performed before the flow rate detection chip 10 is fixed to the support lead 31.

  Moreover, in this embodiment, the example which arrange | positions the filling member 92 after fixing the stopper 50 to the support lead 31 and before a connection process was shown. However, the filling member 92 may be disposed before the molding process.

(Second Embodiment)
Next, 2nd Embodiment of this invention is described based on FIG. FIG. 10 is a plan view showing a schematic configuration of the thermal flow sensor according to the second embodiment, and corresponds to FIG. 1 shown in the first embodiment.

  Since the thermal flow sensor and the manufacturing method thereof according to the second embodiment are in common with the thermal flow sensor 100 and the manufacturing method thereof shown in the first embodiment, a detailed description of the common parts will be omitted below. , Explain the different parts with emphasis. In addition, the same code | symbol shall be provided to the element same as the element shown in 1st Embodiment.

  In 1st Embodiment, the example which makes the stopper 50 cyclic | annular so that the circumference | surroundings of the flow volume detection chip | tip 10 may be enclosed was shown. On the other hand, the present embodiment is characterized in that a plurality of stoppers 50 are fixed on the upper surface of the support lead 31.

  For example, in the example shown in FIG. 10, the stopper 50 is fixed to each of the three end portions excluding the end portion where the pad 20 is formed with respect to the planar rectangular flow rate detection chip 10 (semiconductor substrate 11). Has been. That is, the three stoppers 50 are fixed to the upper surface of the support lead 31 independently (separated) from each other. And the sealing member 70 is arrange | positioned in the clearance gap between each stopper 50 and the flow volume detection chip | tip 10, and it is a surrounding part in the flow direction of a fluid between the edge part of the thermal type flow sensor 100 and a flow volume detection part. The upper surface 72a of 72, the upper surface of the stopper 50, the upper surface 72a of the peripheral portion 72, and the upper surface of the flow rate detection chip 10 are substantially flush. In other words, the present embodiment is the same as the stopper 50 shown in the first embodiment except that there are a plurality of stoppers 50. In addition, the configuration other than that is the same as the configuration shown in the first embodiment except that the gap is filled with the sealing member 70.

  The thermal flow sensor 100 having such a configuration can be formed using the manufacturing method shown in the first embodiment.

  As described above, the manufacturing method of the thermal flow sensor 100 according to the present embodiment also ensures damage to the thin portion 13 and fluctuations in sensor characteristics while ensuring the electrical connection state between the flow detection chip 10 and the external connection lead 32. Can be suppressed. Further, the thermal flow sensor 100 formed by using this manufacturing method ensures an electrical connection state between the flow rate detection chip 10 and the external connection lead 32, and damage to the thin portion 13 and fluctuations in sensor characteristics are prevented. The sensor device is suppressed.

  In the present embodiment, the plurality of stoppers 50 are arranged in a distributed manner. Therefore, the pressure received by the flow rate detection chip 10 from the molds 93 and 94 during molding can be reduced without partial deviation.

  In the present embodiment, the example in which the sealing member 70 is disposed in the gap between each stopper 50 and the flow rate detection chip 10 is shown. However, a configuration in which the sealing member 70 is not disposed in the gap due to the disposition of the filling member 92 illustrated in the first embodiment may be employed. With such a configuration, the range of stress generated based on the difference in linear expansion coefficient between the semiconductor substrate 11 constituting the flow rate detection chip 10 and the stopper 50 can be limited due to a temperature change in the usage environment. That is, fluctuations in sensor characteristics due to the piezoresistance effect can be suppressed.

  Further, in the present embodiment, an example in which the three stoppers 50 are fixed to the upper surface of the support lead 31 is shown. However, the number of stoppers 50 is not limited to three. Further, the arrangement of the plurality of stoppers 50 is not limited to the above example.

  Moreover, in this embodiment, the example which applies the some stopper 50 in the structure shown in 1st Embodiment was shown. However, a plurality of stoppers 50 can also be applied to the modification shown in the first embodiment.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 11 is a cross-sectional view showing a schematic configuration of a thermal flow sensor according to the third embodiment, and corresponds to FIG. 2 shown in the first embodiment.

  Since the thermal flow sensor and the manufacturing method thereof according to the third embodiment are in common with the thermal flow sensor 100 and the manufacturing method thereof shown in the above-described embodiment, a detailed description of the common parts will be omitted below. , Explain the different parts with emphasis. In addition, the same code | symbol shall be provided to the element same as the element shown in the above-mentioned embodiment.

  In the first embodiment, an example in which the stopper 50 as a separate member is fixed to the support lead 31 has been described. On the other hand, this embodiment is characterized in that a convex stopper 31b protruding from the upper surface as a part of the support lead 31 functions as the stopper 50 of the above-described embodiment. The stopper 31b corresponds to the first convex portion described in the claims, and the stopper 50 shown in the first embodiment except that it is formed as a part of the support lead 31. Is the same. Other configurations are the same as the configurations shown in the first embodiment.

  When manufacturing the thermal flow sensor 100 having such a configuration, the stopper 31 b may be formed as a part of the support lead 31 in the step of preparing the lead frame 30. Other steps are the same as those in the manufacturing method shown in the first embodiment.

  Thus, according to the manufacturing method of the thermal flow sensor 100 and the thermal flow sensor 100 according to this embodiment, the manufacturing method of the thermal flow sensor 100 and the thermal flow sensor 100 shown in the first embodiment are the same. The effect can be expected.

  In the present embodiment, the stopper 31 b is formed as a part of the support lead 31. Therefore, the positional accuracy of the upper surface of the stopper 31b with respect to the upper surface of the flow rate detection chip 10 fixed to the support lead 31 can be improved as compared with the stopper 50 as a separate member. That is, the pressure variation of the flow rate detection chip 10 received from the molds 93 and 94 can be further reduced. Further, since the stopper 31b is a part of the support lead 31, a fixing process can be omitted. Further, since the stopper 31b is a part of the support lead 31, it is not necessary to position and fix the stopper 31b at the time of molding, and the mold structure can be simplified.

  In the present embodiment, an example in which the stopper 31b as a part of the support lead 31 is applied to the configuration shown in the first embodiment has been described. However, the stopper 31b can be applied to the modification shown in the first embodiment and the configuration shown in the second embodiment.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 12 is a cross-sectional view illustrating a molding process among the manufacturing processes of the thermal flow sensor according to the fourth embodiment, and corresponds to FIG. 6C illustrated in the first embodiment.

  Since the manufacturing method of the thermal type flow sensor according to the fourth embodiment is often in common with the manufacturing method of the thermal type flow sensor 100 shown in the above-described embodiment, the detailed description of the common parts is omitted below and is different. The part will be explained with emphasis. In addition, the same code | symbol shall be provided to the element same as the element shown in the above-mentioned embodiment.

  In the embodiment described above, an example in which the stopper 50 as a separate member and the stopper 31b as a part of the support lead 31 are formed on the support lead 31 has been described. On the other hand, in this embodiment, as shown in FIG. 12, among the pair of molds 93 and 94 used in the molding process, the upper mold 93 is directed from a part 93b constituting the cavity toward the lower mold 94. A protruding stopper 93d that protrudes is formed. When the stopper 93 d comes into contact with the upper surface of the flow rate detection chip 10 and a part 93 a constituting the cavity of the upper mold 93, the part 94 a constituting the cavity of the lower mold 94 and the support lead 31 are used. It is characterized by the point of contact. The stopper 93d is the same as the stopper 50 shown in the second embodiment except that the stopper 93d is formed as a part of the mold 93. Other configurations are also the same as those shown in the second embodiment.

  As described above, according to the method for manufacturing the thermal flow sensor 100 according to the present embodiment, damage to the thin-walled portion 13 and sensor characteristics are ensured while ensuring an electrical connection state between the flow detection chip 10 and the external connection lead 32. Variations can be suppressed. Further, the thermal flow sensor 100 formed by using this manufacturing method ensures an electrical connection state between the flow rate detection chip 10 and the external connection lead 32, and damage to the thin portion 13 and fluctuations in sensor characteristics are prevented. The sensor device is suppressed.

  Further, according to this embodiment, like the stopper 50 shown in the second embodiment, the plurality of stoppers 93d are formed apart from each other. Therefore, the pressure received by the flow rate detection chip 10 from the molds 93 and 94 during molding can be reduced without partial deviation. According to the manufacturing method shown in the present embodiment, since the stopper 93d is provided as a part of the mold 93, the stopper 93d cannot be annular so as to straddle the wire 91.

  Moreover, in this embodiment, the example in which the stopper 93d is formed only in the metal mold 93 was shown. However, a stopper may be formed on at least one of the pair of molds 93 and 94. For example, convex stoppers are formed on the opposing portions of the molds 93 and 94, respectively, and when the portion 93a constituting the cavity in the upper mold 93 comes into contact with the upper surface of the flow rate detection chip 10, the tips of the stoppers come into contact with each other. It is good also as composition to do. In addition, a convex stopper is formed only on the lower die 94, and when the part 93 a constituting the cavity in the upper die 93 comes into contact with the upper surface of the flow rate detection chip 10, the stopper comes into contact with the facing portion of the upper die 93. It is good also as a structure.

  In the present embodiment, an example in which the stopper 93d as a part of the mold 93 is applied to the configuration shown in the second embodiment. However, the stopper 93d shown in the present embodiment can also be applied to a configuration in which the stopper 50 shown in the second embodiment is applied to a modification of the modification of the first embodiment.

(Fifth embodiment)
Next, 5th Embodiment of this invention is described based on FIG.13 and FIG.14. FIG. 13: is sectional drawing which shows schematic structure of the thermal type flow sensor which concerns on 5th Embodiment. FIG. 14 is a cross-sectional view showing a molding process in the manufacturing process of the thermal flow sensor. 13 corresponds to FIG. 2 shown in the first embodiment, and FIG. 14 corresponds to FIG. 6C shown in the first embodiment.

  Since the thermal flow sensor and the manufacturing method thereof according to the fifth embodiment are in common with the thermal flow sensor 100 and the manufacturing method thereof shown in the above-described embodiment, a detailed description of the common parts will be omitted below. , Explain the different parts with emphasis. In addition, the same code | symbol shall be provided to the element same as the element shown in the above-mentioned embodiment.

  In the embodiment described above, an example in which the flow rate detection chip 10 is directly fixed to the support lead 31 via the adhesive member 90 has been described. On the other hand, in the present embodiment, for example, as shown in FIG. 13, a part of the stopper 50 as a member different from the support lead 31 is an opposing region between the upper surface of the support lead 31 and the lower surface of the flow rate detection chip 10. It is arranged in a part of the gap (that is, facing a part of the lower surface of the flow rate detection chip 10). A part of the lower surface of the flow rate detection chip 10 and the facing portion 50b of the stopper 50 are fixed via an adhesive member 90, and the flow rate detection chip 10 is fixed to the support lead 31 via the facing portion 50b of the stopper 50. It is characterized by that. The adhesive member 90 corresponds to the first adhesive member described in the claims. In the present embodiment, the stopper 50 is the same as the stopper 50 shown in the first embodiment except that the stopper 50 has a portion 50b facing the lower surface of the flow rate detection chip 10. Other configurations are the same as the configurations shown in the first embodiment.

  In the present embodiment, the facing portion 50b of the stopper 50 is opposed to the peripheral portion on the lower surface of the flow rate detection chip 10, and the facing portion 50b is annular. An internal space 95 is formed by the flow rate detection chip 10, the adhesive member 90, the facing portion 50 b of the stopper 50, and the upper surface of the support lead 31, and the cavity 12 is also blocked from the outside air as a part of the internal space 95. .

  In the thermal flow sensor 100 having such a configuration, after fixing the stopper 50 on the support lead 31 in the bonding process, the adhesive member 90 is disposed on the lower surface of the flow rate detection chip 10 or on the opposite portion 50b of the stopper 50, and the stopper It can be formed by fixing the flow rate detection chip 10 on the support lead 31 via the 50 opposing parts 50b. About the other manufacturing process, it is the same as the manufacturing method shown in 1st Embodiment.

  As described above, according to the thermal flow sensor 100 and the manufacturing method thereof according to the present embodiment, it is possible to expect the same effects as the manufacturing method and the thermal flow sensor 100 of the thermal flow sensor 100 shown in the first embodiment. it can.

  In the present embodiment, the facing portion 50 b of the stopper 50 faces only a part of the lower surface of the flow rate detection chip 10. Therefore, as shown in FIG. 14, even when the pressure from the molds 93 and 94 is received during molding and the adhesive member 90 is pushed and spread between the facing portion 50 b of the stopper 50 and the flow rate detection chip 10, the flow rate detection is performed. Since the lower surface of the flow rate detection chip 10 does not exist on the outer peripheral side of the chip 10, the flow rate detection chip 10 is not pulled. Further, since the facing portion 50b of the stopper 50 does not exist on the internal space 95 side and the internal space 95 exists, the adhesive member 90 hangs down to the support lead 31 side and the flow rate detection chip 10 is not pulled. On the other hand, when the flow rate detection chip 10 is directly bonded and fixed to the support lead 31, the spread adhesive member 90 contacts the lower surface of the flow rate detection chip 10. As described above, the range in which the flow rate detection chip 10 is pulled is limited on the facing portion 50b of the stopper 50, so that the thin portion 13 is compared with the configuration in which the flow rate detection chip 10 is directly bonded and fixed to the support lead 31. Damage can be further suppressed.

  Further, since only a part of the lower surface of the flow rate detection chip 10 is in contact with the adhesive member 90, the semiconductor substrate 11 constituting the flow rate detection chip 10 is compared with a configuration in which the entire lower surface is in contact with the adhesive member 90. The stress generated based on the difference in coefficient of linear expansion from the stopper 50 can be reduced.

  In the present embodiment, an example in which no adhesive member is disposed in the internal space 95 is shown. On the other hand, for example, as shown in FIG. 15, an adhesive member 96 in which at least a part of the lower surface of the flow rate detection chip 10 excluding the region facing the stopper 5 and the upper surface of the support lead 31 are harder than the adhesive member 90. It is good also as a structure fixed via. The adhesive member 96 corresponds to the second adhesive member described in the claims, and a member having a Young's modulus after curing larger than that of the adhesive member 90 can be adopted. For example, if a hard adhesive member (eg, Young's modulus of about 1 GPa) that hardly deforms due to pressure is adopted as the adhesive member 96, the flow rate detection chip 10 is equivalent to the area supported on the support lead 31 via the adhesive member 96. Increases the area supported by the support lead 31. Therefore, the durability of the flow rate detection chip 10 against external force (including pressure during molding) can be improved as compared with the configuration in which the adhesive member 96 is not disposed. FIG. 15 is a cross-sectional view showing a modification. In FIG. 15, the adhesive member 96 is disposed adjacent to the facing portion 50b of the stopper 50. However, the adhesive member 96 may be disposed apart from the facing portion 50b.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the present embodiment, the example in which the substrate constituting the flow rate detection chip 10 is the semiconductor substrate 11 made of silicon is shown. When the semiconductor substrate 11 is used in this manner, the cavity 12 and the thin portion 13 can be easily formed in the semiconductor substrate by a general semiconductor manufacturing technique. That is, the thermal flow sensor 100 can be manufactured at low cost. However, the semiconductor substrate is not limited to a silicon substrate. Further, the substrate is not limited to the semiconductor substrate, and a member (for example, glass) having a difference in linear expansion coefficient from the support lead 31 can be employed.

  In the present embodiment, the thermal flow sensor 100 is taken up as an example of the sensor device. This is because the thickness of the thin portion 13 is very thin, about several μm, so that the thin portion 13 is easily damaged during molding, and the sensor characteristics are likely to fluctuate due to the piezoresistance effect. However, the sensor device is not limited to the thermal flow sensor 100. For example, in addition to the thermal flow sensor 100, a sensor having a structure in which a thin portion is formed on a hollow portion of a substrate and a resistor of a detection unit is disposed on the thin portion (for example, a thermopile infrared sensor, a humidity sensor, a pressure sensor) Sensor) or the like.

  In the present embodiment, an example in which the sealing member 70 has the peripheral portion 72 in addition to the pad-side end portion 71 has been shown. However, the form of the sealing member 70 is not limited to the above example. For example, it is good also as a structure which has only the pad side edge part 71. FIG.

  In the present embodiment, an example in which the pad 20 of the flow rate detection chip 10 and the external connection lead 32 are electrically connected via the wire 91 has been shown. However, the connection between the flow rate detection chip 10 and the external connection lead 32 is not limited to wire bonding. For example, when a printed circuit board is used as the support lead 31 and the external connection lead 32 (lead frame 30), the connection may be made by bumps or the like.

  In the present embodiment, an example in which the flow rate detection chip 10 and the external connection lead 32 are directly connected via the wire 91 is shown. However, the flow rate detection chip 10 and the external connection lead 32 may be electrically connected via a circuit chip in which a circuit for controlling input / output of the flow rate detection unit is formed. In this case, the connection portion between the flow rate detection chip and the circuit chip and the connection portion between the circuit chip and the external connection lead are covered with the sealing member 70. As described above, the configuration including the circuit chip can be expected to be the same as or similar to the configuration including no circuit chip.

  In this embodiment, the upper mold | type 93 showed the example which has the recessed part 93c among a pair of metal mold | die 93,94. However, since the stoppers 50, 31b, and 93d are effective, the upper mold 93 may have a structure without the recess 93c.

  In this embodiment, the example which forms the stopper 50 as another member on the support lead 31 was shown. However, for example, as shown in FIG. 16, when a part 93 a constituting the cavity in the upper mold 93 comes into contact with the upper surface of the flow rate detection chip 10, a part of the cavity constituting surface of the upper mold 93 and the cavity of the lower mold 94 are formed. The stopper 51 which is a member different from the support lead 31 may be directly sandwiched between a part of the constituent surfaces. Even if the stopper 51 is not formed on the support lead 31 as described above, the same effect as in the above-described embodiment or an effect equivalent thereto can be expected. In the thermal flow sensor 100 formed using the manufacturing method shown in FIG. 16, the upper surface and the lower surface of the stopper 51 are exposed, and at least a part of the side surface is in contact with the sealing member 70, so that the sealing member 70. Thus, the stopper 51 is held. FIG. 16 is a cross-sectional view showing another modified example of the manufacturing method and shows a molding process.

It is a top view top view which shows schematic structure of the thermal type flow sensor which concerns on 1st Embodiment. It is sectional drawing which follows the II-II line | wire of FIG. It is sectional drawing which follows the III-III line of FIG. It is a top view which shows schematic structure of a flow volume detection chip | tip. It is sectional drawing which follows the IV-IV line of FIG. It is sectional drawing according to process which shows the manufacturing method of a thermal type flow sensor, (a) is the state after completion | finish of an adhesion process, (b) is the state after completion | finish of a connection process, (c) is a figure which shows a formation process. It is sectional drawing which shows a modification. It is sectional drawing which shows a modification. It is sectional drawing which shows the modification of a manufacturing method, (a) is before a formation process, (b) has shown the formation process. It is a top view which shows schematic structure of the thermal type flow sensor which concerns on 2nd Embodiment. It is sectional drawing which shows schematic structure of the thermal type flow sensor which concerns on 3rd Embodiment. It is sectional drawing which shows a formation process among the manufacturing processes of the thermal type flow sensor which concerns on 4th Embodiment. It is sectional drawing which shows schematic structure of the thermal type flow sensor which concerns on 5th Embodiment. It is sectional drawing which shows a formation process among the processes which show a manufacturing method. It is sectional drawing which shows a modification. It is sectional drawing which shows the other modification of a manufacturing method, and has shown the formation process.

Explanation of symbols

10. Flow rate detection chip (sensor chip)
11 ... Semiconductor substrate (substrate)
12 ... Cavity 13 ... Thin part 31 ... Support lead 32 ... External connection lead 50 ... Stopper 70 ... Sealing member 90 ... Adhesive member 100 ... Thermal flow rate Sensor

Claims (17)

A sensor chip in which a detection part and a wiring part connected to the detection part are formed on a substrate having a cavity part, and a resistor constituting the detection part is formed in a thin part on the cavity part, and the sensor A preparation step for preparing a lead frame including a support lead for mounting a chip on one surface and an external connection lead electrically connected to the wiring portion;
An adhesive step of fixing the prepared sensor chip with a lower surface where the hollow portion opens as a mounting surface on the support lead in the lead frame via an adhesive member, and forming a laminate;
A connection step for electrically connecting the external connection lead and the wiring portion in the lead frame to the laminate,
After the connection step, the laminate is placed in a cavity formed in a pair of molds and molded, and the wiring portion and the external connection lead are sealed by a sealing member while exposing the detection portion and the thin portion. A forming step of covering the connection site of the sensor device,
In the molding step, a stopper having a hardness closer to the substrate than the adhesive member is disposed in the cavity, and one mold is in contact with the upper surface of the sensor chip and between the other mold. A method of manufacturing a sensor device, wherein the molding is performed in a state where the stopper is sandwiched.   The method of manufacturing a sensor device according to claim 1, further comprising a fixing step of fixing the stopper on one surface of the support lead before the molding step.   The method of manufacturing a sensor device according to claim 1, wherein, in the preparation step, the convex stopper protruding from the one surface is formed as a part of the support lead. A sensor chip in which a detection part and a wiring part connected to the detection part are formed on a substrate having a cavity part, and a resistor constituting the detection part is formed in a thin part on the cavity part, and the sensor A preparation step for preparing a lead frame including a support lead for mounting a chip on one surface and an external connection lead electrically connected to the wiring portion;
An adhesive step of fixing the prepared sensor chip with a lower surface where the hollow portion opens as a mounting surface on the support lead in the lead frame via an adhesive member, and forming a laminate;
A connection step for electrically connecting the external connection lead and the wiring portion in the lead frame to the laminate,
After the connection step, the laminate is placed in a cavity formed in a pair of molds and molded, and the wiring portion and the external connection lead are sealed by a sealing member while exposing the detection portion and the thin portion. A forming step of covering the connection site of the sensor device,
In the molding step, as at least one of the molds, when the mold on the upper surface side of the sensor chip comes into contact with the upper surface of the sensor chip, directly to the opposite part of the other mold or the support lead A method of manufacturing a sensor device, wherein a mold having a convex stopper that is in contact with each other is used.   The sensor according to claim 1, wherein the sensor chip is a flow rate detection chip including a flow rate detection unit including a heater formed on the thin portion as the detection unit. Device manufacturing method. A sensor chip in which a detection part and a wiring part connected to the detection part are formed on a substrate having a hollow part, and a resistor constituting the detection part is formed in a thin part on the hollow part,
The lead frame is a part of the lead frame, and is electrically connected to the wiring portion on one side, the support lead having the sensor chip fixed through an adhesive member with the open lower surface of the cavity portion as a mounting surface. External connection leads,
A sealing member made of an insulating material and integrally disposed so as to cover a connection portion between the wiring portion and the external connection lead while exposing the detection portion and the thin portion. A sensor device,
A sensor device, wherein a stopper having a hardness closer to the substrate than the adhesive member is formed on one surface of the support lead and excluding the mounting region of the sensor chip.   The sensor device according to claim 6, wherein the stopper is a separate member from the support lead, and is fixed on one surface of the support lead.   The sensor device according to claim 6, wherein the stopper is a first convex portion formed as a part of the support lead.   The sensor device according to claim 6, wherein the stopper is formed on one surface of the support lead and in the vicinity of a mounting area of the sensor chip.   The sensor device according to claim 9, wherein the stopper has a back surface facing the support lead substantially flush with an upper surface of the sensor chip.   The sensor device according to claim 6, wherein the stopper is formed in an annular shape so as to surround the sensor chip. The annular stopper is formed apart from the sensor chip,
Of the gap between the stopper and the sensor chip, a region that is not covered by the sealing member and at least a part of the region from the boundary with the sealing member is a filling member different from the sealing member, or The sensor device according to claim 11, wherein the sensor device is filled with a second protrusion formed as a part of the support lead.   12. The annular stopper is a region that is not covered by the sealing member and is in contact with the sensor chip at least in a region from the boundary with the sealing member. Sensor device.   The sensor device according to claim 6, wherein the sensor chip is directly fixed to the support lead via the adhesive member. A part of the stopper is disposed between one surface of the support lead and the lower surface of the sensor chip, and is opposed to a part of the lower surface of the sensor chip,
A part of the lower surface of the sensor chip and a portion facing the stopper are fixed via a first adhesive member as the adhesive member, and the sensor chip is fixed to the support lead via the stopper. The sensor device according to claim 6, wherein the sensor device is a sensor device.   At least a portion of the lower surface of the sensor chip excluding the opposing region of the stopper and the support lead are fixed via a second adhesive member that is harder than the first adhesive member. The sensor device according to claim 15.   The sensor according to any one of claims 6 to 16, wherein the sensor chip is a flow rate detection chip provided with a flow rate detection unit including a heater formed on the thin portion as the detection unit. apparatus.

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