JP5125978B2 - Sensor device - Google Patents

Description

  The present invention relates to a sensor device in which a sensor chip and a control chip for controlling the sensor chip are attached to a case.

Conventionally, as this type of sensor device, there are a case, a sensor chip that is supported by the case for detection, a control chip that is supported by the case and arranged next to the sensor chip, and controls the sensor chip. A connection member that connects and electrically connects both chips, and a sealing resin that is provided in the case and seals a connection portion between the connection member and the connection member and the both chips has been proposed ( For example, see Patent Document 1).
JP 2007-17352 A

  The inventor made a prototype of the sensor device based on the above-described conventional technology and examined it. FIG. 5 is a diagram showing a schematic cross-sectional configuration of a sensor device as a prototype manufactured by the inventor.

  In FIG. 5, the case 10 is made of resin or the like, and the sensor chip 20 and the control chip 30 are supported on the case 10. Here, a substrate 60 made of ceramic or metal lead frame or the like is insert-molded in the case 10, and both the chips 20 and 30 are bonded to the substrate 60 via an adhesive 70. It is supported by the case 10.

  The sensor chip 20 and the control chip 30 are electrically connected by being connected by a connection member 40 such as a bonding wire. The case 10 is provided with a sealing resin 50 that seals both the chips 20 and 30, and the sealing resin 50 seals the connection member 40 and the connection part between the connection member 40 and both the chips 20 and 30. Has been.

  In this prototype, in particular, the sensor chip 20 is fixed by partial adhesion because its characteristics are likely to vary due to external factors such as temperature and stress. That is, the connection member 40 is connected to one surface of the sensor chip 20, the other surface opposite to the substrate 60 faces the substrate 60, and a part of the other surface is bonded to the substrate 60 via the adhesive 70. Has been.

  Here, since the sensor chip 20 and the control chip 30 are mounted on the same substrate 60 made of ceramic or metal having a high thermal conductivity, the heat generated by the control chip 30 travels through the substrate 60 and the sensor chip. It easily reaches 20 and causes characteristic fluctuations.

  As for the member fixing the sensor chip 20, the sealing resin 50 is provided on one surface of the sensor chip 20, the substrate 60 is provided below the sensor chip 20, that is, the other surface side, and the case 10 is provided therebelow. In addition, materials having different linear expansion coefficients are intricately arranged above and below the sensor chip 20. For this reason, a stress is applied to the sensor chip 20 due to a temperature change, which causes a problem of characteristic fluctuation.

  The present invention has been made in view of the above problems, and in a sensor device in which a sensor chip and a control chip for controlling the sensor chip are attached to a case, heat generated by the control chip is hardly transmitted to the sensor chip, The object is to reduce the stress applied to the sensor chip due to temperature changes.

  In order to achieve the above object, according to the first aspect of the present invention, the sensor chip (20) and the control chip (30) are provided in the case (10), and both the chips (20, 30) are connected by the connecting member (40). In the sensor device formed by connecting and electrically connecting, and sealing the connection member (40) and the connection part between the connection member (40) and both the chips (20, 30) with a sealing resin (50). The connection member (40) is connected to one surface of the chip (20) near the control chip (30), and the other surface of the sensor chip (20) near the control chip (30) is bonded to the adhesive ( 70), the sensor chip (20) is fixed on the case (10) by being directly bonded to the case (10), and the sealing resin (50) is attached to the sensor chip from the control chip (30) side. (20) Extend to the side In addition, the end of the sealing resin (50) on the sensor chip (20) side is at the same position as the end of the adhesive (70) opposite to the end of the control chip (30) side. The portion of the case (10) located immediately below the adhesive (70) is made of the same resin material as the sealing resin (50).

  According to this, since the sensor chip (20) is directly bonded to the case (10) made of a resin having a lower thermal conductivity than that of the conventional substrate, the heat generated in the adjacent control chip (30) is It is difficult to transmit to the sensor chip (20), and sealing is performed to the same position with the same resin material on one side and the other side of the sensor chip (20), that is, on the upper side and the lower side of the sensor chip (20). Therefore, the difference in stress applied to the sensor chip (20) due to temperature change is reduced as much as possible.

  Therefore, according to the present invention, heat generated in the control chip (30) can be hardly transmitted to the sensor chip (20), and stress applied to the sensor chip (20) due to temperature change can be reduced.

Here, like invention of Claim 2, the resin material which comprises the site | part located in the case (10) just under an adhesive agent (70), and the resin material which comprises sealing resin (50) Can be both epoxy resins.
Further, as in the third aspect of the invention, the end portion of the sealing resin (50) on the sensor chip (20) side is closer to the control chip (30) side than the end portion. ) Portion may be configured as a dam portion (51) that prevents the portion from protruding beyond the end portion.

  According to this, since the end part on the sensor chip (20) side in the sealing resin (50) is configured as the dam part (51), the sealing resin located closer to the control chip (30) than the end part. Since the part (50) is blocked by the dam part (51) and does not protrude outside the dam part (51), the position of the end part on the sensor chip (20) side in the sealing resin (50) Can be defined with high accuracy.

  In addition, the code | symbol in the bracket | parenthesis of each means described in the claim and this column is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals in the drawings in order to simplify the description.

(First embodiment)
FIG. 1 is a diagram showing a schematic cross-sectional configuration of the sensor device S1 according to the first embodiment of the present invention. The sensor device according to the present embodiment is employed in various sensors such as a pressure sensor, an acceleration sensor, and an angular velocity sensor. Here, the sensor device will be described as applied to a thermal flow sensor.

  The sensor device S1 of the present embodiment mainly includes a case 10, a sensor chip 20 that is supported by the case 10 and performs detection, a control chip 30 that is supported by the case 10 and controls the sensor chip 20, and both these chips. A connecting member 40 for connecting and electrically connecting 20 and 30; and a sealing resin 50 provided in the case 10 for sealing the connecting member 40 and a connecting portion between the connecting member 40 and both the chips 20 and 30; It is configured with.

  Here, the case 10 is made of an epoxy resin, and has a container shape having a bottom surface in the lower part and an upward opening in FIG. A sensor chip 20 and a control chip 30 are supported on the bottom surface of the case 10.

  The sensor chip 20 is obtained by forming a sensing unit 21 on a semiconductor substrate such as a silicon semiconductor by a general semiconductor process. Here, the sensing part 21 is a thin part compared with the other site | part in the sensor chip 20, The thermal type flow element is formed in this thin part. Heat generated at the center of the thin part is transmitted to the atmosphere, and moves to the periphery of the thin part by the fluid, and the flow rate is detected by sensing the heat.

  The control chip 30 is disposed next to the sensor chip 20 and is electrically connected to the sensor chip 20 via the wiring member 40. By inputting / outputting electric signals to / from the sensor chip 20, the control chip 30 Control and signal extraction are performed.

  Further, on the bottom surface side of the case 10, a substrate 60 made of a ceramic plate material, a metal lead frame or the like similar to the conventional one is insert-molded. The control chip 30 is bonded to the substrate 60 via an adhesive 70 made of resin, whereby the control chip 60 is fixed and supported by the case 10. The adhesive 70 is made of resin, and is disposed, for example, as potting or a sheet.

  Here, the wiring member 40 is a wire formed by wire bonding such as gold or aluminum, but may be a wiring shape such as a ribbon. The wiring member 40 is connected to the surface of the control chip 30 opposite to the bonding surface of the substrate 60, and is connected to one surface of the sensor chip 20 across both the chips 20 and 30.

  In addition, a lead 80 made of conductive metal is insert-molded in the case 10, and the control chip 30 is also connected to the lead 80 by the wiring member 40 and is electrically connected thereto. The lead 80 is electrically connected to the outside, so that the control chip 30 can exchange electrical signals with the outside.

  Here, looking at the connection between the sensor chip 20 and the connection member 40, the sensor chip 20 positions the part opposite to the sensing unit 21 on the control chip 20 side. The connection member 40 is connected to a part of the sensor chip 20 other than the sensing unit 21, that is, one surface of the sensor chip 20 near the control chip 20.

  The other surface of the sensor chip 20 near the control chip 30 is directly bonded to the case 10 made of resin via an adhesive 70. Thereby, the sensor chip 20 is fixed on the case 10 and supported by the case 10. The adhesive 70 that bonds the sensor chip 20 and the adhesive 70 that bonds the control chip 30 may be the same or different.

  The sealing resin 50 is provided by potting, and extends on both the chips 20 and 30 from the control chip 30 side to the sensor chip 20 side. At the same time, the end on the sensor chip 20 side of the sealing resin 50 is the end opposite to the end on the control chip 30 side in the adhesive 70 that bonds the sensor chip 20 to the case 10 (in FIG. 1). It is the same position as the right end of the adhesive 70.

  The arrangement relationship between the sealing resin 50 and the adhesive 70 that bonds the sensor chip 20 will be described more specifically. That is, the sealing resin 50 seals the connection member 40 and the connection part of the control chip 30 with the connection member 40 on the control chip 30, while passing between the control chip 30 and the two chips 20, 30. The chip 20 is continuously provided on one surface.

  The sealing resin 50 that seals one surface of the sensor chip 20 seals the connection member 40 and the connection portion of the sensor chip 20 with the connection member 40, while the end of the sensor chip 20 on the control chip 30 side. 20a and the end 20b on the opposite side extend to the middle, and the end on the sensor chip 20 side of the sealing resin 50 is located in the middle between the both ends 20a, 20b.

  Here, the distance L1 between the end 20a on the control chip 30 side in the sensor chip 20 and the end on the sensor chip 20 side in the sealing resin 50 is the length L1 of the resin that seals the sensor chip. In the present embodiment, this length L1 corresponds to the length L1 of the sealing resin 50 that seals the sensor chip as it is.

  On the other hand, on the lower side of the sensor chip 20 in FIG. 1, that is, on the other side of the sensor chip 20, the adhesive 70 is filled between the case 10 and the sensor chip 20. The adhesive 70 is located between the end 20a and the end 20b opposite to the end 20a.

  The distance L2 between the end 20a of the sensor chip 20 on the control chip 30 side and the end of the adhesive 70 opposite to the end of the control chip 30 is the length of the resin that seals the bottom of the sensor chip. Let L2. Here, the length L2 corresponds to the length L2 of the adhesive 70 located below the sensor chip. At this time, in this embodiment, the lengths L1 and L2 of both resins are the same length.

  Here, the fact that these two lengths L1 and L2 are the same length means that they are the same including an error of ± 10% or less in addition to being completely identical. This is due to processing errors in the process of forming the sealing resin 50 and the adhesive 70.

  That is, as described above, the sealing resin 50 is disposed and cured by resin potting, and the adhesive 70 is disposed and cured by resin potting or disposed as a molded resin sheet. It is. Even if the two lengths L1 and L2 are aimed to be completely the same due to processing errors in the process of forming the sealing resin 50 and the adhesive 70, generally, the lengths L1 and L2 are ± Dimensional error within 10% occurs.

  Therefore, in the present embodiment, if the difference between the lengths L1 and L2 is ± 10% or less, they are regarded as the same. Thus, the control chip in the sensor chip 20 above and below the sensor chip 20 such as the sealing resin 50 on one side and the other side of the sensor chip 20, that is, the adhesive resin 70 on the upper side of the sensor chip 20 in FIG. Sealing with the resins 50 and 70 is performed from the end portion 20a on the 30 side to the same position.

  Furthermore, in the present embodiment, a portion of the case 10 that is located immediately below the adhesive 70 that bonds the sensor chip 20 is made of the same resin material as the sealing resin 50 that is located immediately above the sensor chip 20. .

  Here, the portion of the case 10 that is located immediately below the adhesive 70 is a portion of the case 10 that is located in a region where the adhesive 70 that bonds the sensor chip 20 is projected onto the case 10. And the resin material which comprises the site | part located just under the adhesive agent 70 in case 10 and the resin material which comprises the sealing resin 50 are the same in the composition in the resin material of these both 50 and 70, It means that the physical properties are the same. In this embodiment, both are made of the same epoxy resin.

  As a result, the portion of the case 10 that is located immediately below the adhesive 70 that bonds the sensor chip 20 and the sealing resin 50 that is positioned directly above the adhesive 70 across the sensor chip 20 are made of the same resin material. Therefore, the linear expansion coefficients are also the same.

  In the present embodiment, the resin material constituting the entire case 10 and the sealing resin 50 are the same, as well as the portion of the case 10 that is located directly below the adhesive 70 that bonds the sensor chip 20. It has become.

  Of course, in addition to this, only a portion of the case 10 located immediately below the adhesive 70 is partially made of the same resin material as the sealing resin 50, and the other portions of the case 10 are sealed. The resin 50 may be made of a different resin material. For example, in this embodiment, the resin material and the sealing resin 50 constituting the entire case 10 are both epoxy resins, and the linear expansion coefficient thereof is about 10 ppm.

  A method for manufacturing the sensor device S1 will be described. A case 10 made of an epoxy resin in which a substrate 60 and leads 80 are insert-molded is prepared, and the sensor chip 20 is directly bonded to a resin portion of the case 10 via an adhesive 70. The case 10 is bonded to the substrate 60 via an adhesive 70. Thus, the sensor device S1 is completed.

  Thereafter, wire bonding such as gold or aluminum is performed, and the control chip 30 and the lead 80 and the control chip 30 and one surface of the sensor chip 20 are connected by a wire as the wiring member 40. Thereafter, the sealing resin 50 is arranged by potting so as to satisfy the arrangement relationship with the adhesive 70 described above, and is cured.

  By the way, according to the present embodiment, first, the substrate 60 on which the control chip 30 is mounted does not reach below the sensor chip 20, and the sensor chip 20 is made of a resin having a lower thermal conductivity than the substrate 60. The case 10 is directly bonded. Therefore, the heat generated in the control chip 30 is insulated by the case 10 and hardly transmitted to the sensor chip 20.

  For example, in this embodiment, when the substrate 60 is ceramic, its thermal conductivity is about 10 W / mK, whereas when the substrate 60 is a metal such as copper, its thermal conductivity is 100 W / mK or more. The thermal conductivity of the epoxy resin constituting the case 10 is about 0.5 W / mK, which is very small.

  Further, since the upper and lower sides of the sensor chip 20 are sealed to the same position with the same resin material, the stress is balanced between the upper side and the lower side of the sensor chip 20, and the linear expansion coefficient of the resin material is substantially equal. Since they are the same, the difference in stress applied to the sensor chip 20 due to temperature changes is reduced as much as possible. In other words, the sensor chip 20 is hardly stressed when the temperature changes. The linear expansion coefficient can be adjusted by adjusting the amount of filler in the resin material.

  In addition, it is preferable that the linear expansion coefficient of the adhesive 70 bonding the sensor chip 20 is matched with that of the sealing resin 50 directly above the sensor chip 20 and the case 10 directly below. However, the thickness of the sealing resin 50 immediately above the sensor chip 20 is about 500 μm, and the thickness of the case 10 immediately below is about 1 mm, whereas the thickness of the adhesive 70 is significantly small, about several tens of μm. Therefore, the adhesive 70 is not substantially affected even if the linear expansion coefficient is not matched.

  Thus, according to this embodiment, the heat generated in the control chip 30 can be made difficult to be transmitted to the sensor chip 20, and the stress applied to the sensor chip 20 due to a temperature change can be reduced.

(Second Embodiment)
FIG. 2 is a diagram showing a schematic cross-sectional configuration of the sensor device S2 according to the second embodiment of the present invention. This embodiment is different from the first embodiment in that the sealing resin 50 is deformed, and here, the difference will be mainly described.

  As shown in FIG. 2, in this embodiment, the end portion of the sealing resin 50 on the sensor chip 20 side is configured as a dam portion 51. The dam portion 51 prevents the portion of the sealing resin 50 located closer to the control chip 30 than the dam portion 51 from protruding beyond the dam portion 51.

  The dam portion 51 is a part of the sealing resin 50, and is made of the same resin as the case 10 located immediately below the sealing resin 50 and the sensor chip 20, here, an epoxy resin. In this case, the dam part 51 and the part of the sealing resin 50 located closer to the control chip 30 than the dam part 51 are arranged first.

  At this time, the resin of the dam part 51 is arranged first by potting, and then the part of the sealing resin 50 located on the control chip 30 side than the dam part 51 is arranged, but the dam part 51 is cured first. After that, the latter part may be potted, or the entire part may be cured simultaneously after potting the latter part without curing the dam part 51.

  According to the present embodiment, since the end portion on the sensor chip 20 side in the sealing resin 50 is configured as the dam portion 51, the sealing resin located closer to the control chip 30 than the dam portion 51 as the end portion. 50 portions are blocked by the dam portion 51 and can be prevented from protruding outside the dam portion 51. Therefore, the position of the end portion on the sensor chip 20 side in the sealing resin 50 can be accurately defined.

(Third embodiment)
FIG. 3 is a diagram showing a schematic cross-sectional configuration of a sensor device S3 according to the third embodiment of the present invention. This embodiment is different from the first embodiment in the configuration of the resin that seals the bottom of the sensor chip 20, and here, the difference will be mainly described.

  In the first embodiment, the length L2 of the resin that seals under the sensor chip corresponds to the length L2 of the adhesive 70 that is located under the sensor chip. On the other hand, in this embodiment, as shown in FIG. 3, the length of the adhesive 70 that bonds the sensor chip 20 is shorter than the length L2 of the resin that seals the bottom of the sensor chip. Yes, the sealing resin 50 enters the lower side of the sensor chip 20 correspondingly.

  That is, in the present embodiment, the length L2 of the resin that seals the bottom of the sensor chip is equal to the sealing resin 50 that has entered between the sensor chip 20 and the case 10 below the sensor chip 20, that is, on the other surface side. The combined length with the adhesive 70 is set.

  Also in this case, similarly to the first embodiment, heat generated in the control chip 30 can be hardly transmitted to the sensor chip 20, and stress applied to the sensor chip 20 due to a temperature change can be reduced.

  Note that the adhesive 70 that is located immediately below the sensor chip 20 and adheres the sensor chip 20 in the present embodiment may be the same resin material as the sealing resin 50. In this case, the adhesive 70 can be expected to have the function of the dam portion as shown in the second embodiment on the lower side of the sensor chip 20.

(Fourth embodiment)
FIG. 4 is a diagram showing a schematic cross-sectional configuration of a sensor device S4 according to the fourth embodiment of the present invention. The present embodiment is different from the third embodiment in the configuration of the case 10 located below the sensor chip 20, and here, the difference will be mainly described.

  As shown in FIG. 4, a protrusion 11 that protrudes toward the sensor chip 20 is provided in a portion of the case 10 located below the sensor chip 20, and an adhesive 70 is provided between the tip of the protrusion 11 and the sensor chip 20. Adhesive fixation is carried out with intervening. Thereby, the sealing resin 50 can be easily wound under the sensor chip 20.

(Other embodiments)
In addition, the part located in the case 10 just under the adhesive 70 should just consist of the same resin material as the sealing resin 50, and even if it is the same resin with resin other than the above-mentioned epoxy resin. Good.

  In addition, since heat generated in the control chip 30 is difficult to be transmitted to the sensor chip 20, it is particularly effective when the sensor chip 20 is a thermal flow element as in the above embodiment. In addition, the chip 20 may be a pressure detection element, an acceleration detection element, or the like.

It is a schematic sectional drawing of the sensor apparatus which concerns on 1st Embodiment of this invention. It is a schematic sectional drawing of the sensor apparatus which concerns on 2nd Embodiment of this invention. It is a schematic sectional drawing of the sensor apparatus which concerns on 3rd Embodiment of this invention. It is a schematic sectional drawing of the sensor apparatus which concerns on 4th Embodiment of this invention. It is a schematic sectional drawing of the sensor apparatus as a prototype which this inventor made as a prototype.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Case 20 Sensor chip 30 Control chip 40 Connection member 50 Sealing resin 51 Dam part 70 Adhesive

Claims (3)

Case (10);
A sensor chip (20) supported by the case (10) for detection;
A control chip (30) supported by the case (10) and disposed next to the sensor chip (20) to control the sensor chip (20);
A connecting member (40) for connecting and electrically connecting the sensor chip (20) and the control chip (30);
A sealing resin (50) that is provided in the case (10) and seals the connection member (40) and the connection part between the connection member (40) and the two chips (20, 30). ,
The connection member (40) is connected to one surface of the sensor chip (20) near the control chip (30), and other parts of the sensor chip (20) near the control chip (30). The sensor chip (20) is fixed on the case (10) by directly bonding the surface to the case (10) via an adhesive (70),
The sealing resin (50) extends from the control chip (30) side to the sensor chip (20) side, and an end of the sealing resin (50) on the sensor chip (20) side is bonded to the sealing resin (50). It is in the same position as the end on the opposite side to the end on the control chip (30) side in the agent (70),
A part of the case (10) located immediately below the adhesive (70) is made of the same resin material as the sealing resin (50).   In the case (10), a resin material constituting a portion located immediately below the adhesive (70) and a resin material constituting the sealing resin (50) are both epoxy resins. The sensor device according to claim 1.   The end of the sealing resin (50) on the side of the sensor chip (20) is such that the portion of the sealing resin (50) located on the control chip (30) side of the end exceeds the end. The sensor device according to claim 1, wherein the sensor device is configured as a dam portion (51) that prevents protrusion.

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