JP6416704B2 - Resin-sealed sensor device - Google Patents

Description

  The present invention relates to a resin-sealed sensor device in which a package is formed by resin-sealing a sensor element in which a hollow portion is hermetically sealed.

  In recent years, sensor devices that detect various physical quantities have been developed to improve the stable operation and reliability of automobiles, mobile phones, digital cameras, and the like. In automobiles, the application of acceleration sensors and angular velocity sensors has been expanded particularly for equipment (for example, airbag) control for preventing skidding and improving passenger safety. In addition, in application of a sensor device to an automobile, it is indispensable to reduce the size of the sensor device itself so that the sensor device can be mounted in a limited space such as an electronic control unit housing of a device controlled using sensor output. ing.

  Accelerometers and angular velocity sensors mounted on sensor devices are detection means that use silicon (Si) microfabrication technology (etching, etc.) for the purpose of downsizing, multi-functionality / combination, and mass productivity. Application has become mainstream. For example, a fine comb-like structure of silicon is formed by a microfabrication technique, and physical quantities such as acceleration and angular velocity are detected by converting a minute displacement of the comb-like structure into an electric signal. The comb-like structure is provided in a hollow part inside a laminate made of at least two sensor element substrates (silicon or glass material), and the hollow part is hermetically sealed by the substrate.

  In the packaging of sensor elements having a hollow portion inside, a package forming method by resin sealing that is high in productivity and suitable for reducing manufacturing costs is used. For example, Patent Document 1 describes an example in which a sensor element having a hollow portion is sealed with a resin and packaged. For resin sealing, there is a case where a transfer mold capable of forming a large number of packages in a short time with a single resin sealing may be used. An example of forming a resin-sealed package by transfer molding is described in Patent Document 2.

JP 2010-67853 A JP 2008-91845 A

  When packaging by resin sealing with transfer mold, the sensor element is placed in a mold mold held at a high temperature (about 180 ° C), and then the resin is filled into the mold at high pressure and cured to form a package. To do. During resin molding, a high pressure is also applied to the sensor element. In the sensor element having a hollow portion therein described in Patent Document 1, the portion of the sensor element substrate in which the hollow portion is configured is thinner than the peripheral portion of the substrate other than the hollow portion. When the pressure by the transfer mold is applied, the sensor element substrate in which the hollow portion is formed is deformed, and a high stress is generated at the outer peripheral end of the hollow portion, so that the sensor element substrate may be damaged.

  In the example described in Patent Document 1, since the semiconductor element and the holding member for the lead frame are bonded to one of the sensor element substrates on which the hollow portion is formed, these bonded portions have high rigidity. However, both the semiconductor element and the lead frame holding member size are smaller than the hollow portion outer periphery size. When a high pressure is applied, the holding member of the semiconductor element and the lead frame is easily deformed in the thickness direction integrally with the sensor element substrate. Therefore, even on the sensor element substrate side bonded to the semiconductor element, the substrate may be damaged.

  The deformation of the sensor element substrate also occurs due to expansion and contraction due to a temperature change of the resin that seals the sensor element. In addition to the difference in linear expansion coefficient between the components (silicon, glass, etc.) constituting the sensor element and the sealing resin, the sensor element is deformed due to the difference in the sealing resin thickness within the package. When a high bending stress is generated in the sensor element substrate, the sensor element substrate may be damaged.

  If damage occurs at the end of the hollow part of the sensor element substrate, the hermetic seal of the hollow part cannot be maintained, or the comb-like structure inside the hollow part is also damaged. May decrease.

  The present invention has been made to solve the above problems, and in the hollow portion inside the sensor element for detecting physical quantities such as acceleration and angular velocity, the deformation of the substrate constituting the sensor element is suppressed to prevent the occurrence of damage. In addition, an object of the present invention is to provide a highly reliable resin-sealed sensor device that achieves a reduction in the size of the package.

  In order to solve the above problems, the present invention employs the following configuration.

  Process the signal from the sensor element with a laminate consisting of at least two substrates, an electrode formed so as to penetrate the substrate, and a hermetically sealed hollow portion inside the substrate laminate. In the resin-sealed sensor device in which a package is formed by resin-sealing together with a circuit board that controls signal input / output with the outside of the sensor device, one of the sensor element substrate main surfaces constituting the sensor element is in contact with the resin. The other sensor element substrate is disposed so as to face the circuit board, and is connected to the circuit board. The sensor element substrate thickness in the hollow portion forming region on the side in contact with the resin is thicker than the sensor element substrate facing the circuit substrate, and the circuit substrate covers the projection surface of the hollow portion existing inside the sensor element. Connected to the element.

  By using the above configuration, the stress generated when a high pressure during resin sealing is applied to the sensor element substrate corresponding to the hollow portion forming portion on the side in contact with the resin can be reduced, and the resin can be expanded and contracted. It is also possible to reduce the stress caused by the sensor element deformation. Since the sensor element substrate on the side facing the circuit board is also covered with a circuit board larger than the outer peripheral size of the hollow portion, the sensor element substrate portion corresponding to the hollow portion is not locally deformed, It is possible to suppress the generation of high stress on the sensor element substrate at the outer peripheral end of the hollow portion.

  In the sensor element, an electrode penetrating the substrate is formed on the sensor element substrate in order to output a signal obtained by a detection unit using a microfabrication technique provided inside the hollow part to the outside of the sensor element. In the present invention, an electrode penetrating the sensor element substrate is provided on a substrate disposed so as to face the circuit substrate. Since the sensor element substrate on the side facing the circuit board is connected (or bonded) to the circuit board, the stress generated in the sensor element substrate due to resin sealing pressure or resin expansion / contraction is relieved. Can be made thinner. As a result, the width (or diameter) of the electrode penetrating the substrate can be reduced, and the increase in the planar size of the sensor element can be suppressed. This makes it possible to reduce the size of the sensor device. If the number of electrodes penetrating the substrate provided on the sensor element substrate is small, or if there is a margin in the planar size of the sensor element relative to the package size, the electrode penetrating the sensor element substrate on the side in contact with the resin is used. It can be formed.

  When forming an electrode penetrating the sensor element substrate on the circuit board side, it is necessary to electrically connect the electrode exposed on the surface of the sensor element to an electrode of a semiconductor substrate constituting the circuit board. In the present invention, a relay circuit board having electrodes connected to the sensor element side electrode and the semiconductor substrate side electrode on both upper and lower main surfaces and wiring necessary for electrical conduction is provided between the semiconductor substrate and the sensor element. . As a result, it is possible to make an electrical connection between the sensor element and the semiconductor substrate and also an electrical connection part with the outside of the sensor device.

  In the present invention, a plurality of sensor elements in which a laminate composed of at least two substrates, an electrode formed so as to penetrate the substrate, and a hermetically sealed hollow portion exist inside the substrate laminate, Similarly, in a sensor device in which a package is formed by resin-sealing together with a circuit board, generation of high stress on the sensor element board at the end of the hollow portion can be suppressed. In the plurality of sensor elements, one sensor element substrate main surface constituting each sensor element is in contact with the resin, and the other sensor element substrate is disposed to face the circuit board and connected to the circuit board. The sensor element substrate on the side in contact with the resin is thicker than the sensor element substrate facing the circuit board, and the projection surface of the hollow portion existing inside each sensor element is covered with the circuit board. With such a configuration, generation of high stress on both the resin contact side and the circuit board facing side of the sensor element substrate is suppressed.

  According to the present embodiment, excessive deformation of the substrate constituting the sensor element having a hollow portion in which a detection unit for measuring a predetermined physical quantity is installed is suppressed, stress is reduced, and damage to the sensor element is prevented. In addition, it is possible to provide a highly reliable resin-sealed sensor device corresponding to downsizing.

It is sectional drawing which shows 1st Embodiment of the resin sealing type | mold sensor apparatus by this invention. It is a fragmentary sectional view of the resin-sealed sensor device shown in FIG. FIG. 3 is a partial cross-sectional view showing another aspect of the resin-sealed sensor device shown in FIGS. 1 and 2. FIG. 5 is a cross-sectional view showing still another aspect of the resin-sealed sensor device shown in FIGS. 1 and 2.

Embodiments of the present invention will be described using examples.

  Hereinafter, the resin-sealed sensor device in Example 1 will be described with reference to the drawings.

  FIG. 1 is a sectional view of a resin-sealed sensor device according to the present invention, and FIG. 2 is a partial sectional view of a sensor element and a circuit board.

  As shown in FIGS. 1 and 2, a resin-sealed sensor device 10 according to the present invention includes a circuit board 2 including a semiconductor substrate 3 and a relay substrate 4 and a sensor element 1 stacked in order on a chip pad 5. Has been. The sensor element 1, the circuit board 2 and the chip pad 5 are covered with a resin 9, and form a package 100 together with the inner lead 6 and the outer lead 7.

  The sensor element 1 is electrically connected to the relay substrate 4 by flip chip connection via the protruding electrode 27, and the periphery of the protruding electrode 27 is covered with a filling resin 28 also called underfill resin. The semiconductor substrate 3 and the relay substrate 4 are also electrically connected via wires and electrodes (not shown), and the sensor element 1 and the semiconductor substrate 3 are electrically connected via the relay substrate 4. The relay substrate 4 and the inner lead 6 are electrically connected by a wire 8, and the outer lead 7 integrally formed with the inner lead 6 protrudes from the package 100 and is connected to a device outside the resin-sealed sensor device 10. Is done.

  In the sensor element 1, the cap substrate surface 14 a is disposed so as to face the relay substrate 4, and is electrically connected by the protruding electrode 27 and fixed to the relay substrate 4 by the filling resin 28. The relay substrate 4 constituting the circuit board 2 is disposed on the surface 3a of the semiconductor substrate 3, and is formed integrally with the semiconductor substrate 3 or a substrate manufactured separately is electrically and mechanically connected. The The semiconductor substrate 3 is fixed on the chip pad 5 via a bonding material (not shown).

  The configuration of the sensor element 1 and the connection state with the circuit board 2 will be described in detail with reference to FIG.

  The sensor element 1 has a laminated structure in which a base substrate 12, a detection substrate 13, and a cap substrate 14 are joined in order, and a hollow portion 11 is formed inside the sensor element. The hollow portion 11 is provided with a sensor detection unit 19 formed integrally with the detection substrate 13 and detects, for example, acceleration and angular velocity, and outputs a corresponding detection signal. The detection signal reaches the surface electrode 23 on the cap substrate surface 14a via the pattern wiring 20 and the through electrode 21 formed on the cap substrate, and is electrically connected by the surface electrode 26 of the relay substrate 4 and the protruding electrode 27. Is done. The cap substrate surface 14 a on which the surface electrode 23 is provided is covered with an insulating protective film 22, and the surface electrode 23 is exposed from the protective film 22. The surface electrode 26 of the relay substrate 4 and the bonding electrode 29 of the relay substrate 4 are connected by wiring (not shown), and the wire 8 is connected to the bonding electrode 29.

  The substrate thickness 15 (tb) of the base substrate 12 in the portion where the hollow portion 11 is formed is thicker than the substrate thickness 16 (tc) of the cap substrate 14 in the same hollow portion 11 (tb> tc). In the present invention, as shown in FIG. 1, the base substrate surface 12 a with the thick substrate portion of the hollow portion 11 is in contact with the sealing resin 9, and the cap substrate surface 14 a with the thin substrate thickness is disposed so as to face the semiconductor substrate 3. Has been.

  The width 17 (wc) of the hollow portion 11 inside the sensor element 1 is formed to be smaller than the width 18 (ws) of the semiconductor substrate 3, and the projection surface of the hollow portion 11 is entirely covered by the semiconductor substrate 3.

  In the resin-sealed sensor device 10 of the present invention, the surface 12 a of the base substrate 12 having a thick substrate out of the sensor element substrates 12 and 14 forming the hollow portion 11 of the sensor element 1 is in contact with the sealing resin 9. Arranged on the side. With such an arrangement, it is possible to provide a thicker sensor element substrate (base substrate 12 in this embodiment) on the side on which the resin mold pressure acts directly when forming the package 100, and the substrate of the hollow portion 11 portion due to the mold pressure. Deformation can be suppressed. As a result, the stress of the sensor element substrate generated at the end of the hollow portion 11 can be reduced, and damage to the sensor element substrate can be prevented. Further, the surface 14 a of the cap substrate 14 having a thin substrate thickness is covered with the semiconductor substrate 3 including the projection surface of the hollow portion 11. Even if a resin mold pressure is applied from the resin contact surface side 3b of the semiconductor substrate 3, the pressure is borne by the semiconductor substrate 3 having sufficient rigidity, so that the cap substrate 12 in the hollow portion 11 portion is deformed and high stress is generated. It is possible to suppress this.

  In the resin-sealed sensor device in which the sensor element 1 is sealed with the sealing resin 9 to form the package 100, when the resin sealing is performed at a high temperature (around 180 ° C.) and then cooled, Further, the package 100 may be deformed due to a difference in linear expansion coefficient between the sensor element 1 or the semiconductor substrate 3 and the sealing resin 9. The deformation of the package 100 also affects the sensor element 1 and causes stress to be generated at the end of the hollow portion 11 of the base substrate 12 and the cap substrate 14. In the sensor device 10 of the present invention, the hollow portion 11 portion of the base substrate 12 that is in contact with the sealing resin 9 is thickened to increase the rigidity, so that the effect of reducing stress generated due to deformation of the package 100 can be obtained. . Since the cap substrate 14 side where the substrate of the hollow portion 11 is thin is connected to the semiconductor substrate 3 to ensure rigidity, the same stress reduction effect as that of the base substrate 12 side can be obtained.

  FIG. 3 is a partial sectional view of a sensor element and a circuit board showing another aspect of the first embodiment of the resin-sealed sensor device 10 according to the present invention shown in FIGS.

  The main configuration of the sensor element 1 and the circuit board 2 is the same as that of the embodiment shown in FIG. 1, but the difference is that two hollow portions 11a and 11b are provided inside the sensor element 1. A support member 32 is formed on each of the base substrate 12 and the cap substrate 14, and the hollow portion is divided by supporting the detection substrate 13, thereby forming the hollow portions 11a and 11b. Even in such a configuration, the base substrate thickness 15 (tb) in the hollow portions 11a and 11b is larger than the cap substrate thickness 16 (tc). The widths 17 a and 17 b of the hollow portions 11 a and 11 b are also shorter than the width 18 (ws) of the semiconductor substrate 3, and the projection surfaces of the hollow portions 11 a and 11 b are covered with the semiconductor substrate 3. With the configuration as shown in FIG. 3, the size in the plane direction of the hollow portions 11a and 11b (for example, 17a and 17b) can be reduced, so that the rigidity of the sensor element 1 in the hollow portion can be further increased, and the generated stress Can be further reduced.

  In the first embodiment of the present invention shown in FIG. 1, the sensor element 1 is connected to the relay substrate 4 provided on the semiconductor substrate 3, and the bonding electrode 29 and the inner lead 6 provided on the outer periphery of the relay substrate 4 are wired. 8 is connected. By adopting such a configuration, the distance between the outer peripheral portion of the relay substrate 4 and the inner lead 6 can be narrowed, and the wire 8 can be shortened. When the wire 8 is shortened, the deformation of the wire 8 due to the resin flowing at the time of resin sealing can be suppressed, and the occurrence of a short circuit caused by the contact between the wires 8 or the contact of the wire with the sensor element 1 can be prevented. It becomes possible to do.

  In the present invention, since the sensor element 1, the semiconductor substrate 3, and the chip pad 5 are stacked in the thickness direction of the package 100, the package size can be prevented from expanding in the lateral direction, and the package 100 can be reduced in size. Can also be achieved.

  Further, since no bonding electrode for connecting the wire 8 is provided on the base substrate surface 12a of the sensor element 1, the thickness of the resin 9 between the base substrate surface 12a and the surface of the package 100 can be minimized, and the package It is possible to cope with the thinning of 100.

  In the through electrode 21 provided on the cap substrate 14 shown in FIG. 2 and the like, a conductive material (Au (gold), Ag (silver), Cu (copper), Al (aluminum)) is formed inside the through hole formed by the etching method. Etc.). In the formation of through-holes by etching, the through-hole diameter increases as the through-hole length becomes longer (deeper). Since it is necessary to maintain insulation between the adjacent through electrodes 21, the sensor element 1 having a long through electrode 21 tends to increase in lateral size. In the embodiment shown in FIG. 1 of the present invention, the through electrode 21 is provided on the side of the cap substrate 14 having a thin substrate thickness, taking into consideration the deformation of the substrate due to the resin mold pressure. The size (for example, the hole diameter) does not increase. As a result, the lateral size expansion of the sensor element 1 can be suppressed, and the sensor element 1 and the package 100 can be reduced in size.

  FIG. 4 is a cross-sectional view showing still another aspect of the first embodiment of the resin-sealed sensor device 10 according to the present invention shown in FIG.

  The main configuration of the sensor device 10 is the same as that of the embodiment shown in FIG. 1 except that two sensor elements 1 a and 1 b are mounted on the package 100. The configuration of the sensor element 1 is the same as that of the embodiment shown in FIG. As described above, in the configuration of the sensor element 1 according to the present invention, since the through electrode 21 is provided on the side of the cap substrate 14 having a thin substrate thickness, the lateral size of the sensor element 1 can be reduced. Since the size of the sensor element 1 can be reduced, two sensor elements 1a and 1b (acceleration detection sensor elements, angular velocity detection sensor elements, etc.) having different physical quantities to be detected are arranged in parallel on the surface of the semiconductor substrate 3, and the sensor device 10 Can be combined. Also in the embodiment of FIG. 4, the widths 17c and 17d of the hollow portions 11c and 11d inside the sensor elements 1a and 1b are sufficiently shorter than the width 18 (ws) of the semiconductor substrate 3, and the projection of the hollow portions 11c and 11d. The surface is covered with the semiconductor substrate 3. The base substrate thicknesses 15c and 15d in the hollow portions 11c and 11d are thicker than the cap substrate thicknesses 16c and 16d. Therefore, even if the resin mold pressure is applied, a high stress is not generated on the base substrate 12 and the cap substrate 14 of the sensor elements 11c and 11d, and the resin-encapsulated sensor that can be combined and suppresses damage to the sensor element substrate. A device can be obtained.

  The sensor element 1 is laminated and sealed with a base substrate 12 and a cap substrate 14 made of silicon or glass on the upper and lower sides of a detection substrate 13 having a comb-shaped sensor detection unit 19 formed by finely processing silicon (Si). Formed. The base substrate 12 and the cap substrate 14 corresponding to the formation position of the sensor detection unit 19 are respectively provided with recesses, and the hollow portion 11 is formed when they are stacked. The circuit board 2 includes a semiconductor substrate 3 and a relay substrate 4. In the semiconductor substrate 3, predetermined circuits and electrodes are formed on a silicon substrate by a semiconductor process processing technique. The semiconductor substrate 3 controls the detection operation of the sensor element 1 and performs input / output control of the sensor detection signal inside and outside the package. The relay substrate 4 is made of, for example, a ceramic substrate, a polyimide resin substrate, or a glass epoxy substrate (for example, FR4 or FR5), and a predetermined conductor pattern or electrode is formed on the surface or inside thereof. Alternatively, wiring, electrodes, and insulating layers may be formed on the surface of the semiconductor substrate 3 using the same process as that for forming the semiconductor substrate 3.

  The chip pad 5, the inner lead 6, and the outer lead 7 are assembled in a lead frame state in which they are connected, and are cut from the lead frame after packaging with the mold resin 9. The lead frame is made of a metal material such as a copper alloy (Cu) or an iron nickel alloy (Fe-42Ni). The outer lead 7 is molded into a predetermined shape so that the tip of the lead can be connected to an external mounting substrate or the like. For the wire 8, for example, an Au (gold) fine wire having a diameter of 25 μm is used. The mold resin 9 is a thermosetting epoxy resin filled with silica particles.

  The protruding electrode 27 that electrically connects the surface electrode 23 of the sensor element 1 and the surface electrode 26 of the relay substrate 4 is formed of a stud bump such as gold (Au) or copper (Cu), and is soldered or conductively bonded. Joining with an agent. A thermosetting epoxy resin or the like is used for the filling resin covering the periphery of the protruding electrode 27.

  DESCRIPTION OF SYMBOLS 1 ... Sensor element, 2 ... Circuit board, 3 ... Semiconductor substrate, 4 ... Relay board, 5 ... Chip pad, 6 ... Inner lead, 7 ... Outer lead, 8 ... Wire, 9 ... Sealing resin, 10 ... Sensor device, 11 ... Hollow part, 12 ... Base substrate, 13 ... Detection substrate, 14 ... Cap substrate, 21. ..Penetration electrode, 100 ... package,

Claims (3)

A laminate having a first substrate, an electrode formed so as to penetrate the first substrate, a second substrate thicker than the first substrate thickness, and a hermetically sealed hollow portion A sensor element that is
A circuit board for processing a signal from the sensor element and controlling signal input / output with the outside,
In the resin-sealed sensor device in which the sensor element and the circuit board are both sealed with resin to form a package,
The sensor element is arranged such that the main surface of the second substrate is in contact with the resin, and the main surface of the first substrate is opposed to the circuit board.
The projection surface when projecting the circuit board from the stacking direction covers the projection surface when projecting the hollow portion from the stacking direction ,
A resin-sealed sensor device , wherein a thickness of a region of the second substrate in which the hollow portion is formed is greater than a thickness of a region of the first substrate in which the hollow portion is formed .
A laminate having a first substrate, an electrode formed so as to penetrate the first substrate, a second substrate thicker than the first substrate thickness, and a hermetically sealed hollow portion A sensor element that is
A circuit board for processing a signal from the sensor element and controlling signal input / output with the outside,
In the resin-sealed sensor device in which the sensor element and the circuit board are both sealed with resin to form a package,
The sensor element is arranged such that the main surface of the second substrate is in contact with the resin, and the main surface of the first substrate is opposed to the circuit board.
The projection surface when projecting the circuit board from the stacking direction covers the projection surface when projecting the hollow portion from the stacking direction,
The circuit board is composed of a semiconductor substrate and a relay circuit board for electrical connection between the sensor element and the semiconductor substrate .
In claim 1,
The circuit board, the semiconductor substrate and the sensor element and the resin-sealed sensor apparatus characterized by being composed of a relay circuit board for electrically connecting between the semiconductor substrate.

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