JP4894669B2 - Sensor device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor device capable of securing an electric connection state between a sensor chip and an external connection lead, and suppressing a damage sustained by a thin-walled part or a fluctuation of sensor characteristics. <P>SOLUTION: This sensor device includes the sensor chip wherein a detection part and a wiring part connected to the detection part are formed on a substrate having a hollow part, and a resister constituting the detection part is formed on the thin-walled part on the hollow part; a support lead which is a part of a lead frame, wherein the sensor chip is fixed through an adhesive member on one surface with the opened under surface of the hollow part as a loading surface, and the external connection lead connected electrically to the wiring part; and a sealing member comprising an insulating material, and arranged integrally to cover a connection portion between the wiring part and the external connection lead, while exposing the detection part and the thin-walled part. A plurality of adhesive members having each mutually-different Young's modulus are arranged side by side between the sensor chip and the support lead as the adhesive members, and the sensor chip is fixed to the support lead through the plurality of adhesive members. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention has a sensor chip in which a resistor of a detection unit is formed in a thin part on a cavity, and the thin part and the detection unit are exposed in a state where the sensor chip is arranged on a support lead. In particular, the present invention relates to a sensor device molded in the above and a manufacturing method thereof.

  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.

  Therefore, the present inventor studied a configuration in which the entire lower surface is an adhesive surface and the sensor chip (semiconductor substrate) is bonded and fixed to the support lead (die bond). However, when a soft adhesive member (one that deforms under pressure, 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, stress due to the difference in linear expansion coefficient between the semiconductor substrate and the support lead occurs due to the curing process of the adhesive member or the temperature change in the usage environment, and the stress acts on the thin part of the semiconductor substrate with low rigidity. 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, an object of the present invention is to provide a sensor device in which an electrical connection state between a sensor chip and an external connection lead is ensured and damage to a thin portion and fluctuations in sensor characteristics are suppressed. .

  In order to achieve the above object, according to the first aspect of the present invention, 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 provided on the cavity. A sensor chip formed on the thin wall portion of the lead frame and a part of the lead frame, and a support lead in which the sensor chip is fixed via an adhesive member with the lower surface opened of the cavity portion as a mounting surface on one surface, and The external connection lead electrically connected to the wiring part and made of an insulating material are integrally arranged so as to cover the connection part between the wiring part and the external connection lead while exposing the detection part and the thin part. A plurality of adhesive members having different Young's moduli are arranged side by side as an adhesive member between the sensor chip and the support lead, and the plurality of adhesive members are interposed between the sensor chip and the support lead. Sensor chip is the support lead Characterized in that it is fixed.

  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 secured.

  In addition, a plurality of adhesive members having different Young's moduli are arranged side by side as adhesive members between the sensor chip and the support leads. Among the plurality of adhesive members, an adhesive member having a large Young's modulus has a smaller deformation amount at the time of molding than other adhesive members (an adhesive member having a small Young's modulus). Thereby, the deformation of the sensor chip, and consequently the concentration of stress on the thin portion is suppressed. That is, the damage received by the thin portion is suppressed.

  Among the plurality of adhesive members, the adhesive member having a low Young's modulus has the ability to relieve stress generated based on the difference in linear expansion coefficient between the substrate constituting the sensor chip and the support lead. It is high compared with a large adhesive member). As a result, the stress acting on the thin portion of the sensor chip based on the difference in coefficient of linear expansion is reduced, and consequently fluctuations in sensor characteristics due to the piezoresistance effect are suppressed.

  In the first aspect of the present invention, as described in the second aspect, as the plurality of adhesive members, the first adhesive member fixed to the peripheral region of the cavity portion on the lower surface of the sensor chip, and the first adhesive member The Young's modulus is greater than that of the adhesive, and the lower surface of the sensor chip is fixed to the region between the peripheral region of the cavity and the region corresponding to the portion covered with the sealing member on the upper surface of the sensor chip. It is preferable that the sensor chip is fixed to the support lead via the first adhesive member and the second adhesive member.

  Since the peripheral region of the hollow portion is a region close to the thin portion on the lower surface of the sensor chip, the stress based on the difference in linear expansion coefficient has a great influence on the variation in sensor characteristics. On the other hand, in the present invention, the first adhesive member having a Young's modulus smaller than that of the second adhesive member is fixed in the peripheral region of the cavity. As a result, the stress acting on the thin portion of the sensor chip based on the difference in linear expansion coefficient is effectively reduced, and as a result, fluctuations in sensor characteristics due to the piezoresistance effect are effectively suppressed.

  In addition, on the lower surface of the sensor chip, the region between the peripheral region of the cavity and the covering region corresponding to the portion covered with the sealing member on the upper surface of the sensor chip is pressed against the mold on the upper surface of the sensor chip. The holding area corresponding to the portion to be included is included. In this pressing area, the pressure received by the adhesive member during molding is higher than in other areas. On the other hand, in this invention, the 2nd adhesive member with a larger Young's modulus than the 1st adhesive member is being fixed to the area | region between the surrounding area | region and the coating | coated area | region. This effectively suppresses deformation of the sensor chip and consequently concentration of stress on the thin wall portion. That is, the damage received by the thin portion is effectively suppressed.

  In the invention described in claim 2, as described in claim 3, the surrounding area of the cavity portion may include an area corresponding to the detection section. According to this, the variation in sensor characteristics due to the piezoresistance effect is effectively suppressed not only in the portion located on the thin portion of the detection unit but also in the entire detection unit.

  In the invention according to any one of claims 1 to 3, as described in claim 4, the second adhesive member corresponds to a portion of the wiring portion connected to the external connection lead on the lower surface of the sensor chip. It is preferable that the configuration be arranged in the region.

  In the present invention, the second adhesive member having a large Young's modulus is disposed immediately below the connection portion (that is, the pad) with the external connection lead in the wiring portion. Thereby, a favorable connection state is ensured between the sensor chip and the external connection lead.

Next, in the invention described in claim 5, 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 and a part of the lead frame, and electrically connected to the support lead on which the sensor chip is arranged on the one surface with the open lower surface of the cavity as a mounting surface, and the wiring part The external connection lead, the interposition member interposed between the sensor chip and the support lead, and the insulating material, 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 the sealing is molded member comprises, interposed member is disposed in contact with the entire lower surface of the sensor chip, a portion only, the sensor chip and the support in the stacking direction of the sensor chip and the supporting leads Lead and Is a constant, the remaining portion is characterized by not being at least one the fixed sensor chip and support leads.

  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 secured.

Further, only a part of the interposition member is fixed to the sensor chip and the support lead in the stacking direction of the sensor chip and the support lead. That is, only a part of the interposition member is bonded to both the lower surface of the sensor chip and one surface of the support lead, and the sensor chip is fixed to the support lead through a part of the interposition member . As a result, the range of stress generated based on the difference in linear expansion coefficient between the substrate constituting the sensor chip and the support lead is narrowed compared to the configuration in which the entire lower surface of the sensor chip is bonded and fixed, and the sensor characteristics due to the piezoresistive effect Fluctuations are suppressed.

Further, only a part of the interposition member is fixed to the sensor chip and the support lead in the stacking direction of the sensor chip and the support lead. For this reason, compared to the configuration in which the entire lower surface of the sensor chip is bonded to both the sensor chip and the support lead, even if the interposition member is spread out during molding, the deformation range is reduced, and consequently the thin portion Stress concentration is suppressed. That is, the damage received by the thin portion is suppressed. An intervening member is also arranged in a region where the sensor chip is not bonded and fixed to the support lead in a region facing the lower surface of the sensor chip and the upper surface of the support lead. As a result, the sensor chip is stably supported on the support lead via the interposition member, and fluctuations in sensor characteristics are effectively suppressed. Moreover, the damage which a thin part receives is suppressed effectively .

In the invention described in claim 5, as described in claim 6, the intervening member is a portion of the lower surface of the sensor chip that is covered with the peripheral region of the cavity and the sealing member on the upper surface of the sensor chip. It is preferable that the structure is fixed to the support lead while being fixed to the area between the areas corresponding to. On the lower surface of the sensor chip, the region between the peripheral region of the cavity and the covered region corresponding to the portion covered with the sealing member on the upper surface of the sensor chip is a portion pressed by the mold on the upper surface of the sensor chip during molding. The holding area corresponding to is included. In this pressing region, the pressure received by the intervening member is larger than that in other regions during molding. On the other hand, in the present invention, the region is bonded to the interposition member and fixed to the support lead between the surrounding region and the covering region. Therefore, if an interposition member that hardly deforms even when subjected to pressure is disposed in the region, the deformation of the sensor chip, and hence the concentration of stress on the thin portion is suppressed, and the damage received by the thin portion is suppressed.

  Further, since the peripheral region of the cavity is a region close to the thin portion on the lower surface of the sensor chip, the stress based on the difference in linear expansion coefficient has a great influence on the variation in sensor characteristics. On the other hand, in the present invention, the sensor chip is not fixed to the support lead in the peripheral region of the cavity. That is, no stress is generated based on the difference in linear expansion coefficient between the substrate and the support lead. As a result, the stress acting on the thin portion of the sensor chip based on the difference in linear expansion coefficient is effectively reduced, and as a result, fluctuations in sensor characteristics due to the piezoresistance effect are effectively suppressed.

  In the invention described in claim 6, as described in claim 7, the surrounding area of the cavity portion may include an area corresponding to the detection section. Since the effect of this invention is the same as the effect of the invention of Claim 3, the description is abbreviate | omitted.

In the invention according to claim 6 or claim 7, as in claim 8, the intervening member is a region corresponding to a portion of the lower surface of the sensor chip covered by the sealing member on the upper surface of the sensor chip. Both may be configured to be fixed to the support lead while being fixed.

  In the present invention, the sensor chip is fixed to the support lead immediately below the connection portion (that is, the pad) with the external connection lead in the wiring portion. Thereby, a favorable connection state is ensured between the sensor chip and the external connection lead.

In the invention according to any one of claims 5-8, as described in claim 9, as an intervening member, have a single adhesive member, only a portion of one adhesive member, the sensor chip and the supporting leads The sensor chip and the support lead may be fixed in the stacking direction, and the remaining part may not be fixed to at least one of the sensor chip and the support lead . According to this, the configuration can be simplified.

According to a tenth aspect of the present invention, the interposition member includes a plurality of adhesive members having different Young's moduli, and the adhesive member having the largest Young's modulus among the plurality of adhesive members is a sensor chip and a support lead. It may be a fixed configuration. According to this, the deformation of the sensor chip at the time of molding, and the concentration of stress on the thin portion is suppressed, and the damage received by the thin portion is suppressed.

  In the invention according to any one of claims 1 to 10, as described in claim 11, a flow rate detection chip provided with a flow rate detection unit including a heater formed on a thin portion as a detection unit is used as a sensor chip. It is particularly effective in configuration.

  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 it is set as the structure in any one of Claims 1-10, the electrical connection state of a flow volume detection chip and an external connection lead is ensured, and the damage which a thin part receives and the fluctuation | variation of a sensor characteristic were suppressed. It can be set as a flow sensor device.

  Next, in the invention described in claim 12, the detection unit and the wiring unit connected to the detection unit are formed on the substrate having the cavity, and the resistor constituting the detection unit is formed in the thin portion on the cavity. A preparatory process for preparing the formed sensor chip, a support lead for mounting the sensor chip on one surface, and a lead frame including an external connection lead electrically connected to the wiring portion, and the prepared sensor chip through the cavity The mounting surface is fixed to the support lead in the lead frame with the adhesive member as the mounting surface, and the external connection leads and the wiring part in the lead frame are electrically connected to the laminate. And connecting the wiring part to the external connection connector by the sealing member while exposing the detection part and the thin-walled part. A method of manufacturing a sensor device comprising: a molding step for covering a connection portion with a plurality of contacts; and a plurality of adhesions having different Young's moduli as adhesive members between the sensor chip and the support lead in the adhesion step. The members are arranged side by side, and the sensor chip is fixed to the support lead via at least one adhesive member.

  As described above, according to the present invention, in the bonding step, a plurality of bonding members having different Young's moduli are arranged side by side as bonding members between the sensor chip and the support lead. Then, the sensor chip is fixed to the support lead via at least one adhesive member. Thereby, the sensor device according to claim 1 or the sensor device according to claim 10 can be formed.

  In the twelfth aspect of the invention, for example, as in the thirteenth aspect, in the bonding step, the first bonding member and the second bonding having a larger Young's modulus than the first bonding member are used as the plurality of bonding members. A second adhesive member is disposed on the lower surface of the sensor chip on the lower surface of the sensor chip, excluding the peripheral region of the sensor chip, at least in a region corresponding to a portion where the upper surface of the sensor chip is pressed by the mold at the time of molding. The first adhesive member is disposed in the peripheral area of the part, and the first adhesive member and the second adhesive member are cured with the sensor chip disposed on the support lead to fix the sensor chip to the support lead. May be.

  According to this, since the 2nd adhesive member with a large Young's modulus corresponding to the part pressed down by a model at the time of mold fabrication is arranged, the damage which a thin part receives at the time of mold fabrication can be controlled.

  In addition, since the first adhesive member having a Young's modulus smaller than that of the second adhesive member is disposed in the peripheral region of the cavity, the substrate and the support lead may be affected by heating in the curing process or temperature change in the usage environment. Even if stress is generated based on the difference in linear expansion coefficient, it can be mitigated by the second adhesive member in contact with the peripheral region of the hollow portion close to the thin portion. That is, fluctuations in sensor characteristics due to the piezoresistance effect can be suppressed.

  In addition, since the first adhesive member and the second adhesive member are cured with the sensor chip disposed, the manufacturing process can be simplified.

  In the bonding step, the first bonding member and the second bonding member having a higher Young's modulus than the first bonding member are used as the plurality of bonding members in the bonding step. The first adhesive member is disposed in any one of the peripheral region of the cavity and the region corresponding to the peripheral region on one surface of the support lead, and the curing process is performed on the first adhesive member. A region excluding the peripheral region of the cavity on the lower surface of the substrate, and a region excluding a region corresponding to a region where the upper surface of the sensor chip is pressed by the mold at the time of molding and a region corresponding to the peripheral region on one surface of the support lead The second adhesive member is arranged in a state where the second adhesive member is disposed at least in one of the regions corresponding to the pressing region and the sensor chip is disposed on the support lead. Subjected to hardening treatment may be fixed to the sensor chip to the supporting lead.

  According to this, since the second adhesive member having a large Young's modulus is arranged corresponding to the portion pressed by the mold at the time of molding and the sensor chip is bonded and fixed to the support lead, the damage received by the thin portion at the time of molding Can be suppressed.

  In addition, with respect to the first adhesive member disposed in the peripheral region of the cavity, the curing process is performed before the sensor chip is disposed on the support lead. It is not bonded and fixed to the area corresponding to the surrounding area. Therefore, in this region, no stress is generated based on the difference in coefficient of linear expansion between the substrate and the support lead due to the temperature change in the usage environment, so that fluctuations in sensor characteristics due to the piezoresistance effect can be suppressed. .

  In addition, a part of the lower surface of the sensor chip is adhesively fixed to the support lead, but the first adhesive member is also disposed as an adhesive member in the peripheral region of the cavity that is not adhesively fixed. Therefore, it is possible to stably support the sensor chip on the support lead via the adhesive member, and thereby it is possible to suppress uneven stress on the substrate during molding.

Next, in the invention described in claim 15, 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. A preparatory process for preparing the formed sensor chip and 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 part, and interposing an interposition member, The prepared sensor chip is placed on the support lead in the lead frame with the lower surface where the cavity is open as the mounting surface, and the bonding process for forming the laminate, and the external connection leads and the wiring part in the lead frame to the laminate Electrical connection process, and after the connection process, the laminate is placed in a cavity formed in the mold and molded, and the wiring part is connected to the external part by the sealing member while exposing the detection part and the thin part. A method of manufacturing a sensor device including a forming step of coating a connecting portion between the lead and, in the bonding step, the interposed member, while positioned in contact with the entire lower surface of the sensor chip, as an intervening member, only partially, the adhesive function possess for both the one surface of the sensor chip of the lower surface and the support leads in the laminating direction of the sensor chip and the supporting lead, rest, to at least one of the sensor chips and supporting lead The sensor chip is fixed to the support lead using a member that does not have an adhesive function .

As described above, according to the present invention, as the interposition member , only a part thereof uses a member having an adhesive function with respect to both the lower surface of the sensor chip and one surface of the support lead in the stacking direction of the sensor chip and the support lead. Thereby, the sensor device according to claim 5 can be formed.

In the invention of the fifteenth aspect, for example, as described in the sixteenth aspect, the intervening member is an area excluding the peripheral area of the cavity portion on the lower surface of the sensor chip, and at least the upper surface of the sensor chip is a mold at the time of molding. A member having an adhesive function is used in the region corresponding to the pressing region corresponding to the pressing region and the region corresponding to the pressing region, except for the region corresponding to the peripheral region on one surface of the support lead. Also good.

According to this, the sensor chip is bonded and fixed to the support lead in correspondence with the portion pressed by the mold at the time of molding. Therefore, if a member having a Young's modulus that hardly deforms under pressure is employed as the interposed member , damage to the thin portion during molding can be suppressed. In particular, if a member having a Young's modulus that hardly deforms when subjected to pressure is used as the interposed member , damage to the thin portion can be effectively suppressed.

  Further, the peripheral area of the cavity in the sensor chip and the area corresponding to the peripheral area of the support lead are not bonded and fixed. Therefore, in this region, no stress is generated based on the difference in coefficient of linear expansion between the substrate and the support lead due to the temperature change in the usage environment, so that fluctuations in sensor characteristics due to the piezoresistance effect can be suppressed. .

In addition, while a part of the lower surface of the sensor chip is bonded and fixed to the support lead, a portion of the intervening member that does not have an adhesive function is also disposed in the peripheral region of the cavity portion that is not bonded and fixed. Therefore, the sensor chip can be stably supported on the support lead via the interposition member , and thereby, stress deviation in the substrate during molding can be suppressed.

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. 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 FIG. 1 and FIG. 2 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 via the adhesive member 50, 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 flow rate detection chip 10 and a sealing member 70 that covers a connection portion between the external connection lead 32 and the external connection lead 32. 1 and 2 indicates a wire that electrically connects the flow rate detection chip 10 and the external connection lead 32.

  The flow rate detection chip 10 includes a thin part (membrane) 13 composed of a thin insulating layer formed on the cavity part 12 by forming the cavity part 12 in the semiconductor substrate 11 made of silicon by etching, and a thin part. 13 and a heater 14 formed on the heater 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. 3 and 4. FIG. 3 is a plan view showing a schematic configuration of the flow rate detection chip. 4 is a cross-sectional view taken along line IV-IV in FIG. In FIG. 3, for the sake of convenience, the heater, the temperature sensing element, and the interlayer insulating film and the protective film on the connecting wiring are omitted. Moreover, the white arrow shown in FIG. 3 has shown the flow direction (normal time) of the fluid.

  As shown in FIGS. 3 and 4, a cavity 12 is formed in the semiconductor substrate 11 corresponding to the pair of heaters 14 (14 a, 14 b) that constitute 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. 3). 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. 3) 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 together with the heaters 14a and 14b constitute a flow rate detection unit. 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 90 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 a material different from the semiconductor substrate 11 constituting the flow rate detection chip 10 and has a large difference in linear expansion coefficient (for example, a difference in linear expansion coefficient from the semiconductor substrate 11 such as 42 alloy or Cu). 5 or more materials). 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 50, 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.

  The adhesive member 50 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, two types of adhesive members 51 and 52 having different Young's moduli are employed as the adhesive member 50, and the adhesive member 50 faces the lower surface of the flow rate detection chip 10 and the upper surface of the support lead 31. Arranged throughout the area.

  Specifically, as the first adhesive member 51, a soft adhesive member having a Young's modulus (for example, about 1 MPa) that is deformed by receiving pressure in the cured state is adopted, and the second adhesive member 52 is used. As described above, a hard adhesive member having a Young's modulus (for example, about 1 GPa) that hardly deforms under pressure after being cured is employed. That is, the second adhesive member 52 employs an adhesive member having a higher Young's modulus than the first adhesive member 51. As shown in FIG. 2, the first adhesive member 51 and the second adhesive member 52 are disposed on the lower surface of the semiconductor substrate 11 (the upper surface of the support lead 31) between the flow rate detection chip 10 and the support lead 31. The flow rate detection chip 10 is fixed to the support lead 31 via the adhesive members 51 and 52.

  More specifically, as shown in FIGS. 2 and 3, the first adhesive member 51 is disposed corresponding to the peripheral region surrounding the cavity 12 (opening 16) on the lower surface of the flow rate detection chip 10. In the present embodiment, the area surrounded by the alternate long and short dash line shown in FIG. 3 on the lower surface of the flow rate detection chip 10 is the contact area with the first adhesive member 51 on the lower surface of the flow rate detection chip 10 (around the cavity 12). Area) corresponding to the entire area where the flow rate detection unit is formed. Further, a region excluding the peripheral region of the cavity 12 on the lower surface of the flow rate detection chip 10, and a region corresponding to at least the peripheral region of the cavity 12 and the portion covered with the sealing member 70 on the upper surface of the flow rate detection chip 10. The second adhesive member 52 is disposed corresponding to the region between the two. In the present embodiment, the region surrounded by the two-dot chain line shown in FIG. 3, that is, the entire region excluding the peripheral region of the cavity 12, is the contact region with the second adhesive member 52 on the lower surface of the flow rate detection chip 10. It has become. Therefore, the second adhesive member 52 is also disposed on the lower surface of the flow rate detection chip 10 in a region corresponding to the pad 20 that is a connection portion with the wire 90.

  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, for example, a wire 90 made of 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. 10 are electrically connected.

  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 wire 90, the connection portion between the wire 90 and the flow rate detection chip 10 (pad 20), and the connection portion between the wire 90 and the external connection lead 32. Yes.

  In the present embodiment, the sealing member 70 is connected not only to the pad-side end portion 71 that covers each of the connection portions described above but also to the pad-side end portion 71 to form the pad 20 of the flow rate detection chip 10. The peripheral portion 72 is disposed so as to surround the remaining three end surfaces (side surfaces of the semiconductor substrate 11) excluding the end surface on the end portion side. The peripheral portion 72 is in contact with the end surface of the flow rate detection chip 10, and the upper surface 72 a thereof is substantially flush with the upper surface of the flow rate detection chip 10. In other words, in the fluid flow direction, the flow rate detection unit to the end of the peripheral portion 72 of the sealing member 70 are flush with each other, and the fluid is more rectified on the flow rate detection unit. In other words, with respect to the flow rate detection unit, the end surface 71a on the flow rate detection unit side and the upper surface 72a of the peripheral portion 72 (and the upper surface of the flow rate detection chip 10) in the pad side end 71 arranged on the flow rate detection chip 10 are used. Thus, a flow path is formed.

  Next, the manufacturing method of the thermal type flow sensor 100 comprised in this way is demonstrated using Fig.5 (a)-(c). FIGS. 5A and 5B are cross-sectional views illustrating a method for manufacturing the thermal flow sensor 100, wherein FIG. 5A is a diagram illustrating a bonding process, FIG. 5B is a connection process, and FIG. 5A to 5C 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 that is a part of the lead frame 30 with the lower surface as the bonding surface. In this adhesive fixing, the adhesive member 50 may be disposed on the upper surface of the support lead 31, or the adhesive member 50 may be disposed on the lower surface of the flow rate detection chip 10.

  In the present embodiment, as shown in FIG. 5A, film-like (sheet-like) adhesive members 51 and 52 having substantially the same thickness are arranged on the upper surface of the support lead 31 in the above-described regions. Then, the flow rate detection chip 10 is arranged on the adhesive members 51 and 52 so that the lower surface thereof is in contact with the adhesive members 51 and 52 arranged side by side on the support lead 31, and in this state, the curing process of the adhesive members 51 and 52 is performed. Do. As a result, the flow rate detection chip 10 is fixed to the support lead 31 via the adhesive members 51 and 52. That is, a stacked body in which the flow rate detection chip 10 is stacked on the support lead 31 is formed. Specifically, the area around the cavity 12 in the flow rate detection chip 10 is fixed to the support lead 31 via the first adhesive member 51, and the area excluding the area around the cavity 12 in the flow rate detection chip 10 is the first. It is fixed to the support lead 31 via a second adhesive member 52 having a higher Young's modulus after curing than the adhesive member 51. Thus, since the hardening process of the some adhesive members 51 and 52 is implemented at the same process, a manufacturing process can be simplified.

  Next, as shown in FIG. 5B, the pad 20 (see FIGS. 1 and 3) 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 90 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. In addition, wire bonding is performed with 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 being bonded and fixed via the second adhesive member 52. As a result, a better bonded state can be formed. As a result, as shown in FIG. 5B, the flow rate detection chip 10 (pad 20) and the external connection lead 32 are electrically connected via the wire 90.

  Next, the laminated body after wire bonding is placed in the cavities formed in the dies 91 and 92, and in a state where the dies are clamped, the molten sealing member is injected into the cavities and integrally molded. As a result, as shown in FIG. 5C, the flow rate detection unit including the thin portion 13 is exposed in the laminate, and the wire 90, the connection portion between the wire 90 and the flow rate detection chip 10 (pad 20), and the wire 90. And the connection part between the external connection lead 32 and the sealing member 70 are integrally covered.

  In the present embodiment, as shown in FIG. 5C, the lower surface of the flow rate detection chip 10 is a region excluding the peripheral region of the cavity 12, and at least the upper surface of the flow rate detection chip 10 at the time of molding is the mold 91. The second adhesive member 52 is disposed in a region corresponding to the part pressed by the pressing portion 91a. Further, in order to prevent the thin portion 13 from being damaged by the stress due to mold clamping, a recess 91 b is provided in a portion of the mold 91 that faces the thin portion 13 that faces the thin portion 13. Therefore, the adhesive member 50 hardly deforms during molding.

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

  Then, after molding, 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 FIG.1 and FIG.2 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, the linear expansion coefficient is different between the semiconductor substrate 11 constituting the flow rate detection chip 10 and the support lead 31. Stress based on the difference in 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 the present embodiment, the first adhesive member in which the area around the cavity 12 in the lower surface of the flow rate detection chip 10 has a Young's modulus smaller than that of the second adhesive member 52 and is deformed by pressure. It is fixed to the support lead 31 through 51. Therefore, the stress based on the difference in coefficient of linear expansion between the semiconductor substrate 11 constituting the flow rate detection chip 10 and the support lead 31 is relieved by the first adhesive member 51 that is a part of the adhesive member 50. In particular, the stress based on the difference in linear expansion coefficient generated in the peripheral region of the cavity portion 12 is effectively relieved by the first adhesive member 51 in contact with the peripheral region of the cavity portion 12. Thereby, compared with the case where the adhesive member 50 is comprised only by the 2nd adhesive member 52, the stress transmitted to the thin part 13 is reduced, and the fluctuation | variation of the sensor characteristic by a piezoresistive effect is suppressed.

  In the present embodiment, the peripheral region of the cavity 12 includes the entire region corresponding to the flow rate detection unit formation region. Therefore, in the flow rate detection unit, not only the resistor located on the thin portion 13 but also the entire flow rate detection unit is effectively suppressed from changing sensor characteristics due to the piezoresistance effect.

  Further, in the configuration in which the flow rate detection chip 10 is disposed on the support lead 31, as an adhesive member for fixing the flow rate detection chip 10 to the support lead 31, a soft adhesive member (one that is deformed by pressure after curing, for example, When the Young's modulus is about 1 MPa, the thin-walled portion 13 is damaged by the pressure when the mold is clamped, and may be broken 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. It is considered that a stress is generated in the thin film portion 13 and the stress is concentrated on the thin portion 13. In particular, at the time of molding, the pressure received by the adhesive member is higher in the region pressed by the pressing portion of the mold than in the other regions.

  On the other hand, in this embodiment, a region (including a region pressed by the pressing portion 91 a of the mold 91) of the lower surface of the flow rate detection chip 10 excluding the peripheral region of the cavity portion 12 is from the first adhesive member 51. Also, the Young's modulus is large, and it is fixed to the support lead 31 via the second adhesive member 52 that hardly deforms even under pressure. Therefore, even when the second adhesive member 52 is pressed by the pressing portion 91a of the mold 91 at the time of molding, the second adhesive member 52 is hardly deformed, so that the deformation of the flow rate detection chip 10 is suppressed. Thus, concentration of stress on the thin portion 13 is suppressed. That is, the damage received by the thin portion 13 is suppressed.

  Further, the flow rate detection chip 10 is bonded and fixed to the support lead 31, whereby the thermal flow rate sensor 100 according to this embodiment ensures an electrical connection state between the flow rate detection chip 10 and the external connection lead 32. Is done. In the present embodiment, not only the region between the peripheral region of the cavity 12 on the lower surface of the flow rate detection chip 10 and the region corresponding to the portion covered with the sealing member 70 on the upper surface of the flow rate detection chip 10 is used. The second adhesive member 52 is disposed over the entire region excluding the peripheral region of the cavity 12. That is, the second adhesive member 52 is also disposed below the pad 20. Therefore, a better connection state is ensured between the flow rate detection chip 10 and the external connection lead 32.

  As described above, in the thermal flow sensor 100 according to the present embodiment, the electrical connection state between the flow 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. It is a sensor device.

  In the present embodiment, an example is shown in which the peripheral region of the cavity 12 that the first adhesive member 51 contacts on the lower surface of the flow rate detection chip 10 includes all the regions corresponding to the flow rate detection unit formation region. However, resistance value fluctuations due to the piezoresistive effect are most likely to occur in the heater 14 formed in the thin portion 13. Therefore, it is good also as a structure where the surrounding area | region of the cavity part 12 does not contain the area | region corresponding to the formation area of the temperature sensing bodies 18a and 18b among flow volume detection parts.

  Further, in the present embodiment, the example in which the entire region except the peripheral region of the cavity 12 on the lower surface of the flow rate detection chip 10 is fixed to the support lead 31 via the second adhesive member 52 has been shown. However, at the time of molding, the portion of the adhesive member 50 that contacts the region corresponding to the pressing portion 91a of the die 91 is most easily deformed. Therefore, the second adhesive member 52 may be arranged only in the region pressed by the pressing portion 91a of the mold 91.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a cross-sectional view showing a schematic configuration of the thermal flow sensor according to the second embodiment, and corresponds to FIG. 2 shown in the first embodiment. FIGS. 7A and 7B are diagrams showing an adhesion process in an example of the manufacturing method of the thermal flow sensor shown in FIG. 6. FIG. 7A shows the first adhesion, and FIG. 7B shows the second adhesion.

  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 the first embodiment, the example in which the flow rate detection chip 10 is fixed to the support lead 31 via the first adhesive member 51 and the second adhesive member 52 has been described. That is, the example in which the flow rate detection chip 10 is fixed to the support lead 31 in the entire adhesive member 50 is shown. On the other hand, in this embodiment, as shown in FIG. 6, only a part of the adhesive member 50 is a flow rate detection chip in the stacking direction of the flow rate detection chip 10 and the support lead 31 (hereinafter simply referred to as the stacking direction). 10 and the support lead 31 are fixed.

  Also in the present embodiment, the first adhesive member 51 is disposed corresponding to the peripheral region surrounding the cavity 12 (opening 16) on the lower surface of the flow rate detection chip 10. The first bonding member 51 is bonded to only the support lead 31 without being bonded to the flow rate detection chip 10, and the bonding portion 51 a is configured only between the support lead 31. In addition, the second adhesive member 52 is disposed corresponding to the entire region except the peripheral region of the cavity 12 on the lower surface of the flow rate detection chip 10. The second adhesive member 52 is bonded to both the support lead 31 and the flow rate detection chip 10, and an adhesive portion 52 a is formed between the support lead 31 and the flow rate detection chip 10. Yes. The other configuration is the same as the configuration shown in the first embodiment.

  As described above, according to the thermal flow sensor 100 according to the present embodiment, only a part of the adhesive member 50 is bonded to both the flow detection chip 10 and the support lead 31 in the stacking direction. That is, the flow rate detection chip 10 is fixed to the support lead 31 via a part of the adhesive member 50. As a result, the range of stress generated based on the difference in linear expansion coefficient between the semiconductor substrate 11 and the support lead 31 constituting the flow rate detection chip 10 is narrowed compared to the configuration in which the entire lower surface of the flow rate detection chip 10 is bonded and fixed. The fluctuation of sensor characteristics due to the piezoresistive effect is suppressed.

  In particular, in the present embodiment, among the adhesive members 50, the first adhesive member 51 in contact with the peripheral region of the cavity 12 on the lower surface of the flow rate detection chip 10 is at least one of the flow rate detection chip 10 and the support lead 31 in the stacking direction. (In this embodiment, it is not bonded to the flow rate detection chip 10). That is, the flow rate detection chip 10 is not fixed to the support lead 31 via the adhesive member 50 in the peripheral region of the cavity 12, which is a region close to the thin portion 13 on the lower surface of the semiconductor substrate 11, and is supported with the semiconductor substrate 11. Stress based on the difference in linear expansion coefficient with the lead 31 does not occur. Thereby, the stress which acts on the thin part 13 of the flow rate detection chip 10 based on the linear expansion coefficient difference is effectively reduced, and the fluctuation of the sensor characteristic due to the piezoresistance effect is effectively suppressed.

  In addition, since only a part of the adhesive member 50 is bonded to both the flow rate detection chip 10 and the support lead 31 in the stacking direction, even if the adhesive member 50 is expanded during molding, the deformation range is the flow rate. This is reduced compared to a configuration in which the entire lower surface of the detection chip 10 is bonded and fixed. That is, the concentration of stress on the thin portion 13 is suppressed, and as a result, damage to the thin portion 13 is suppressed.

  In particular, in the present embodiment, the second adhesive member 52 in contact with a region (including a region pressed by the pressing portion 91a of the mold 91) excluding the peripheral region of the cavity 12 on the lower surface of the flow rate detection chip 10 is It is bonded to both the flow rate detection chip 10 and the support lead 31. Therefore, as shown in the first embodiment, even when the second adhesive member 52 is pressed by the pressing portion 91a of the mold 91 at the time of molding, the second adhesive member 52 hardly deforms. The deformation of the flow rate detection chip 10 is suppressed, and the stress concentration on the thin portion 13 is suppressed. That is, the damage received by the thin portion 13 is effectively suppressed.

  Further, the surrounding area of the cavity portion 12 on the lower surface of the flow rate detection chip 10 is configured not to be bonded and fixed to the support lead 31, but the cavity portion of the opposed region between the lower surface of the flow rate detection chip 10 and the upper surface of the support lead 31. The first adhesive member 51 is disposed in contact with the 12 surrounding regions. That is, the adhesive member 50 is disposed in contact with the entire lower surface of the flow rate detection chip 10. Therefore, the flow rate detection chip 10 is stably supported on the support lead 31 through the adhesive member 50, and stress deviation in the semiconductor substrate 11 during molding is suppressed. Thereby, the fluctuation | variation of a sensor characteristic and the damage which the thin part 13 receives are suppressed.

  Next, an example of a manufacturing method of the thermal flow sensor 100 configured as described above will be described. First, as a first bonding step, the first bonding member 51 is disposed in a predetermined region on the support lead 31 and a curing process is performed. As a result, the first adhesive member 51 is cured, and an adhesive portion 51 a is formed between the first adhesive member 51 and the support lead 31 as shown in FIG. After the effect processing of the first adhesive member 51, the second adhesive member 52 is disposed in a predetermined region on the support lead 31 as the second adhesive process, and the first adhesive member 51 and the second adhesive member 52 The flow rate detecting chip 10 is stacked. And a hardening process is implemented in this lamination | stacking state. As a result, the second adhesive member 52 is cured, and as shown in FIG. 7B, an adhesive portion 52a is formed between the second adhesive member 52 and the support lead 31, and the second adhesive member. An adhesive portion 52 b is configured between the flow rate detection chip 10 and the flow rate detection chip 10. Since the first bonding member 51 is cured before the second bonding step, the first bonding member 51 is not bonded to the flow rate detection chip 10 even when the first bonding member 51 is cured in the second bonding step. As a result, as shown in FIG. 7B, only the second adhesive member 52 of the adhesive member 50 is bonded to both the support lead 31 and the flow rate detection chip 10. The above is the bonding process. Since the steps after the bonding step (connection step, molding step) are the same as those in the manufacturing method shown in the first embodiment, description thereof is omitted.

  In the present embodiment, an example in which only a part of the adhesive member 50 is fixed to the flow rate detection chip 10 and the support lead 31 in the stacking direction by performing the bonding process in two stages has been described. However, the method of forming a configuration in which a part of the adhesive member 50 is selectively adhered to both the flow rate detection chip 10 and the support lead 31 is not limited to the above example. For example, in the example shown in FIG. 8, the first adhesive member 51 has a cover member 53 that does not have an adhesive function on the contact surface side with the flow rate detection chip 10. According to this, the hardening process of the 1st adhesive member 51 and the 2nd adhesive member 52 can be implemented in the same process. FIG. 8 is a cross-sectional view showing a modification.

  In addition, in a state where the first adhesive member 51 and the second adhesive member 52 are arranged on the upper surface of the support lead 31 (or the lower surface of the flow rate detection chip 10), a part of the adhesive member 50 is selectively cured (for example, Alternatively, the flow rate detection chip 10 may be fixed to the support lead 31 via a part of the adhesive member 50.

  Further, as the first adhesive member 51 and the second adhesive member 52, a sheet-like adhesive member (adhesive tape) in which an adhesive material is applied to the surface of the base material may be employed. As the first adhesive member 51, a single-sided adhesive tape in which the base material does not have an adhesive function and an adhesive material is disposed on one side of the base material is adopted, and as the second adhesive member 52, both surfaces of the base material are used. What is necessary is just to employ | adopt the double-sided adhesive tape by which the adhesive material was arrange | positioned. In addition, as the 1st adhesive member 51, although the adhesive material is not arrange | positioned on both surfaces of a base material is also employable, it becomes the structure by which the 1st adhesive member 51 is not fixed at all. Therefore, a configuration having an adhesive material on one side is preferable.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 9 is a cross-sectional view illustrating a schematic configuration of a thermal flow sensor according to the third embodiment. FIG. 9 corresponds to FIG.

  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 embodiments, detailed descriptions of the common parts are 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 to embodiment mentioned above.

  In the second embodiment, as an example in which a part of the adhesive member 50 is fixed to the flow rate detection chip 10 and the support lead 31 in the stacking direction, of the first adhesive member 51 and the second adhesive member 52, In the example, only the second adhesive member 52 is fixed to the flow rate detection chip 10 and the support lead 31. That is, an example is shown in which some of the plurality of adhesive members are fixed to the flow rate detection chip 10 and the support lead 31. In contrast, in the present embodiment, as shown in FIG. 9, the adhesive member 50 is composed of one adhesive member 54, and only a part of the adhesive member 54 is attached to the flow rate detection chip 10 and the support lead 31 in the stacking direction. Characterized by a fixed point.

  Similar to the second adhesive member 52 described above, the adhesive member 54 is a hard adhesive member having a Young's modulus (for example, about 1 MPa) that hardly deforms under pressure, and is provided on the lower surface of the flow rate detection chip 10 and the upper surface of the support lead 31. It is arrange | positioned at the whole opposing area | region. As shown in FIG. 9, portions of the adhesive member 54 corresponding to the region excluding the peripheral region of the cavity 12 on the lower surface of the flow rate detection chip 10 are selectively disposed in the stacking direction. It adheres to both of 31. That is, in a region excluding the peripheral region of the cavity portion 12, an adhesive portion 54 a is configured between the adhesive member 54 and the support lead 31, and an adhesive portion 54 b is configured between the adhesive member 54 and the flow rate detection chip 10. Yes. Further, a portion of the adhesive member 54 corresponding to the peripheral region of the cavity 12 on the lower surface of the flow rate detection chip 10 is not bonded to the flow rate detection chip 10 but is bonded only to the support lead 31. That is, an adhesive portion 54 a is formed over the entire surface between the adhesive member 54 and the support lead 31.

  Even with such a configuration, the same effect as the configuration shown in the second embodiment can be expected.

  In addition, since only one adhesive member 54 is disposed between the flow rate detection chip 10 and the support lead 31, the configuration can be simplified.

  In the present embodiment, an adhesive material is disposed only on one side of the portion corresponding to the peripheral region of the cavity 12 with respect to a base material that does not have an adhesive function as the adhesive member 54, and the periphery of the cavity 12. A sheet-like adhesive member (adhesive tape) in which an adhesive material is disposed on both sides is adopted at a portion corresponding to the region excluding the region. Thereby, the thermal type flow sensor 100 shown in FIG. 9 is comprised. However, the method for manufacturing the thermal flow sensor 100 shown in FIG. 9 is not limited to the above example. For example, as shown in the modification of FIG. 8, by disposing a cover member that does not exhibit an adhesive function on a part of the adhesive member 54, only a part of the adhesive member 54 is allowed to flow in the stacking direction. It may be bonded to both of the support leads 31. Further, as shown in the modification of FIG. 8, a part of the adhesive member 54 is selectively cured in a state where the adhesive member 54 is disposed on the upper surface of the support lead 31 (or the lower surface of the flow rate detection chip 10) ( For example, by selectively irradiating with UV), only a part of the adhesive member 54 may be bonded to both the flow rate detection chip 10 and the support lead 31 in the stacking direction.

  Further, in the present embodiment, an example is shown in which the portion of the adhesive member 54 corresponding to the peripheral region of the cavity portion 12 is bonded only to the support lead 31. However, for example, as shown in FIG. 10, portions of the adhesive member 54 other than the portion that adheres to both the flow rate detection chip 10 and the support lead 31 in the stacking direction are not only the flow rate detection chip 10 but also the support lead 31. It is good also as a structure which does not adhere | attach. Even in such a configuration, the part that does not adhere to either the flow rate detection chip 10 or the support lead 31 is connected to the part that adheres to both the flow rate detection chip 10 or the support lead 31. Can be suppressed. FIG. 10 is a cross-sectional view showing a modification.

  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, and 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 90 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, the example in which the flow rate detection chip 10 and the external connection lead 32 are directly connected via the wire 90 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 example which has the 1st adhesive member 51 and the 2nd adhesive member 52 from which Young's modulus mutually differs as the adhesive member 50 was shown. However, the plurality of adhesive members having different Young's moduli are not limited to the two types of adhesive members 51 and 52. The adhesive member 50 may include three or more types of adhesive members having different Young's moduli.

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 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 an adhesion process, (b) is a connection process, (c) is a figure which shows a molding process. It is sectional drawing which shows schematic structure of the thermal type flow sensor which concerns on 2nd Embodiment. It is a figure which shows the adhesion process in an example of the manufacturing method of the thermal type flow sensor shown in FIG. 6, (a) has shown 1st adhesion | attachment, (b) has shown 2nd adhesion | attachment. It is sectional drawing which shows a modification. 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 modification.

Explanation of symbols

10. Flow rate detection chip (sensor chip)
11 ... Semiconductor substrate (substrate)
12 ... Cavity 13 ... Thin portions 14, 14a, 14b ... Heater 31 ... Support lead 32 ... External connection leads 50, 54 ... Adhesive member 51 ... First adhesion Member 52 ... Second adhesive member 70 ... Sealing member

Claims (16)

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 sensor device comprising: 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 Because
Between the sensor chip and the support lead, a plurality of adhesive members having different Young's moduli are arranged side by side as the adhesive member, and the sensor chip is fixed to the support lead via the plurality of adhesive members. A sensor device. As a plurality of the adhesive members,
On the lower surface of the sensor chip, a first adhesive member fixed to the peripheral region of the cavity,
The Young's modulus is larger than that of the first adhesive, and on the lower surface of the sensor chip, the peripheral region of the cavity and the region corresponding to the portion covered with the sealing member on the upper surface of the sensor chip, An intermediate region and a fixed second adhesive member,
The sensor device according to claim 1, wherein the sensor chip is fixed to the support lead via the first adhesive member and the second adhesive member.   The sensor device according to claim 2, wherein a surrounding region of the hollow portion includes a region corresponding to the detection unit.   The said 2nd adhesion member is arrange | positioned in the area | region corresponding to the site | part of the said wiring part connected with the said external connection lead in the lower surface of the said sensor chip. The sensor device according to item. 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,
A support lead that is a part of the lead frame, and on one surface, the support chip on which the sensor chip is arranged with the lower surface opened of the cavity portion as a mounting surface; and an external connection lead electrically connected to the wiring portion; ,
An interposition member interposed between the sensor chip and the support lead;
A sealing member made of an insulating material and molded 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,
The interposition member is disposed in contact with the entire lower surface of the sensor chip, and only a part thereof is fixed to the sensor chip and the support lead in the stacking direction of the sensor chip and the support lead, and the remaining portion. Is not fixed to at least one of the sensor chip and the support lead . The interposition member is fixed to the area between the peripheral area of the cavity and the area corresponding to the portion covered by the sealing member on the upper surface of the sensor chip on the lower surface of the sensor chip, The sensor device according to claim 5, wherein the sensor device is fixed to the support lead.   The sensor device according to claim 6, wherein a surrounding region of the hollow portion includes a region corresponding to the detection unit. The interposition member is fixed to the support lead while being fixed to a region corresponding to a portion of the upper surface of the sensor chip covered by the sealing member on the lower surface of the sensor chip. Item 8. The sensor device according to item 6 or item 7. As the intermediate member, it has a single adhesive member,
Only a part of the one adhesive member is fixed to the sensor chip and the support lead in the stacking direction of the sensor chip and the support lead, and the remaining part is fixed to at least one of the sensor chip and the support lead. It is not carried out , The sensor apparatus of any one of Claims 5-8 characterized by the above-mentioned. As the interposition member , having a plurality of adhesive members having different Young's moduli from each other,
The sensor device according to claim 5, wherein an adhesive member having the largest Young's modulus among the plurality of adhesive members is fixed to the sensor chip and the support lead.   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. apparatus. 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 connecting step, the laminate is placed in a cavity formed in a mold and molded, and the connection part between the wiring part and the external connection lead is formed by a sealing member while exposing the detection part and the thin part. A method of manufacturing a sensor device comprising:
In the bonding step, a plurality of bonding members having different Young's moduli are arranged side by side as the bonding member between the sensor chip and the support lead, and the sensor chip is disposed via the at least one bonding member. A method of manufacturing a sensor device, wherein the sensor device is fixed to a support lead. In the bonding step, a first bonding member and a second bonding member having a Young's modulus larger than the first bonding member are used as the plurality of bonding members,
In the lower surface of the sensor chip, the second adhesive member is disposed in a region excluding the peripheral region of the cavity, and at least in a region corresponding to a portion where the upper surface of the sensor chip is pressed by the mold at the time of molding, Disposing the first adhesive member in a peripheral region of the cavity,
13. The sensor chip is fixed to the support lead by curing the first adhesive member and the second adhesive member in a state where the sensor chip is disposed on the support lead. A method for manufacturing the sensor device according to claim 1. In the bonding step, a first bonding member and a second bonding member having a Young's modulus larger than the first bonding member are used as the plurality of bonding members,
The first adhesive member is disposed in one of the peripheral area of the cavity on the lower surface of the sensor chip and the area corresponding to the peripheral area on one surface of the support lead, and subjected to a curing process.
After the curing process of the first adhesive member, a pressing region corresponding to a region where at least the upper surface of the sensor chip is pressed by the mold at the time of molding, the region excluding the peripheral region of the cavity on the lower surface of the sensor chip, And the second adhesive member is disposed in any one of the areas excluding the area corresponding to the peripheral area on one surface of the support lead and corresponding to at least the pressing area, and the second adhesive member is disposed on the support lead. 13. The method of manufacturing a sensor device according to claim 12, wherein the second adhesive member is cured in a state in which the sensor chip is disposed, and the sensor chip is fixed to 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 interposing member is interposed, and the prepared sensor chip is disposed on the support lead in the lead frame with the lower surface where the hollow portion is opened as a mounting surface, and an adhesion step for 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 connecting step, the laminate is placed in a cavity formed in a mold and molded, and the connection part between the wiring part and the external connection lead is formed by a sealing member while exposing the detection part and the thin part. A method of manufacturing a sensor device comprising:
In the bonding step, the interposition member is disposed so as to be in contact with the entire lower surface of the sensor chip, and only a part of the interposition member is disposed in the sensor chip and the support lead in the stacking direction of the sensor chip. It has a bonding function for both the one surface of the lower surface and the supporting lead, rest, using a member that does not have an adhesive function to at least one of the sensor chip and the support leads, the sensor chip A method of manufacturing a sensor device, wherein the sensor device is fixed to the support lead . The interposition member is a region excluding the peripheral region of the cavity on the lower surface of the sensor chip, and at least a pressing region corresponding to a portion where the upper surface of the sensor chip is pressed by the mold at the time of molding, and the support lead 16. The method of manufacturing a sensor device according to claim 15, wherein a region excluding a region corresponding to the surrounding region on one surface and corresponding to at least a region corresponding to the pressing region has an adhesive function.

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