JP2014102225A - Physical quantity sensor and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a stress to be applied to a sensing part.SOLUTION: As a sensor chip 20, grooves 59 and 74 are formed at both ends in a direction which is orthogonal to the protruding direction of a sensing part 21 with respect to a sealing member 40 in a portion sealed by the sealing member 40, and relaxing members 60 and 77 whose Young's modulus is lower than that of the sealing member 40 are used for a region including the grooves 59 and 74. Thus, it is possible to reduce a stress to be applied from the sealing member 40 by the relaxing members 60 and 77, and to suppress the deterioration of detection accuracy.

Description

  The present invention includes a sensor chip on which a sensing unit that outputs a sensor signal corresponding to a physical quantity is formed, and a sealing member that seals a part of the sensor chip so that the sensing unit is exposed and cantilever-supports the sensor chip. The present invention relates to a physical quantity sensor and a manufacturing method thereof.

  Conventionally, for example, Patent Document 1 discloses a sensor chip in which a sensing unit that outputs a sensor signal corresponding to a physical quantity is formed, and a part of the sensor chip is sealed and cantilevered so that the sensing unit is exposed. There has been proposed a physical quantity sensor including a sealing member.

  Specifically, in this physical quantity sensor, the sensor chip has a rectangular planar shape, and a sensing unit that outputs a sensor signal corresponding to the pressure of the measurement medium is formed on one end in the longitudinal direction. . And the other end part side opposite to the one end part side is sealed with a sealing member and cantilevered so that the sensing part is exposed.

  In such a physical quantity sensor, for example, the sensor chip is sealed by appropriately increasing the length in the longitudinal direction of the sensor chip as compared with a physical quantity sensor in which the entire back surface of the sensor chip is fixed to a mounted member such as a substrate. By moving away from the stopping member, stress such as thermal stress applied from the sealing member can be relaxed in a region located between the sensing portion and the sealing member in the sensor chip. For this reason, it can suppress that stress is applied to a sensing part from a sealing member, and it can control that detection accuracy falls.

JP 2012-42392 A

  However, even in the physical quantity sensor, it is difficult to completely eliminate the stress applied from the sealing member to the sensing unit, and it is desired to further reduce the stress applied to the sensing unit.

  In the above description, the sensing unit that outputs a sensor signal corresponding to stress is described as an example. However, the same problem occurs when the sensing unit outputs a sensor signal corresponding to acceleration or angular velocity. .

  An object of this invention is to provide the physical quantity sensor which can reduce the stress applied to a sensing part in view of the said point, and its manufacturing method.

  In order to achieve the above object, in the first aspect of the present invention, a sensor chip having a sensing portion (21) having one surface and another surface opposite to the one surface and outputting a sensor signal corresponding to a physical quantity is formed. 20) and a sealing member (40) that cantilever-supports the sensor chip by sealing a part of the sensor chip while exposing the sensing portion, and the sensor chip is sealed by the sealing member Grooves (59, 74) are formed at both ends in a direction orthogonal to the protruding direction of the sensing portion with respect to the sealing member, and a relaxation member (60, 77) having a Young's modulus lower than that of the sealing member in the region including the groove. It is characterized by being arranged.

  According to this, the stress sealed from the sealing member by the relaxing member can be relaxed, and it is possible to suppress a decrease in detection accuracy. Moreover, since the stress sealed from the sealing member by the relaxing member can be relaxed, the sealing member can be prevented from peeling from the sensor chip.

  For example, as in the invention described in claim 2, the sensor chip includes a sensor part (50) in which a sensing part is formed and a joining member (70, 110) joined to the sensor part. The sensor part groove is formed as the groove (59) in the part, the joint member groove is formed as the groove (74) in the joining member, and the relaxing member includes the sensor part groove and the joining member groove. It can be arranged in a region.

  In this case, as in the invention described in claim 3, the sensor portion groove and the bonding member groove can be connected.

  According to this, since the relaxation member is disposed on the entire side surface of the sensor chip 20 that is sealed with the sealing member, the stress can be further relaxed.

  A fifth aspect of the present invention is an invention relating to the manufacturing method of the first to fourth aspects of the present invention, comprising the steps of preparing a sensor chip wafer (100) having a plurality of chip formation regions, and chip formation. In each of the regions, after the step of forming the grooves in the portions positioned at both ends in the direction orthogonal to the projecting direction among the portions sealed by the sealing member after being divided into chip units, and after the step of forming the grooves In each of the chip formation regions, after the step of disposing the relaxing member in the region including the groove and the step of disposing the relaxing member, the sensor chip wafer is divided into chips along the dicing line to include the groove. A step of forming a plurality of sensor chips each having a relaxation member disposed in the region; and a step of sealing a part of the sensor chip with a sealing member while exposing the sensing portion. It is characterized by a door.

  According to this, it is possible to simultaneously manufacture a plurality of sensor chips on which relaxation members are arranged. That is, for example, after dividing into chips, the manufacturing process can be simplified as compared with the method in which the relaxation member is arranged for each chip.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is sectional drawing of the physical quantity sensor in 1st Embodiment of this invention. (A) is a front view of a sensor chip, (b) is a back view of the sensor chip, and (c) is a side view of the sensor chip. It is sectional drawing along the III-III line in Fig.2 (a). FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. It is sectional drawing which shows the manufacturing process of the sensor chip shown in FIG. FIG. 6 is a cross-sectional view showing a manufacturing process subsequent to FIG. 5. FIG. 5A is a surface view corresponding to FIG. 5B, and FIG. 5B is a surface view corresponding to FIG. (A) is a back view corresponding to FIG. 6 (a), (b) is a back view corresponding to FIG. 6 (b). It is sectional drawing of the physical quantity sensor in other embodiment of this invention. It is sectional drawing of the sensor chip of the physical quantity sensor in other embodiment of this invention.

  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 will be described with the same reference numerals.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. In this embodiment, a physical quantity sensor including a sensor chip in which a sensing unit that detects pressure is formed will be described.

  As shown in FIG. 1, the physical quantity sensor of the present embodiment includes a substrate 10, a sensor chip 20 mounted on the substrate 10, a connection terminal 30 that electrically connects the sensor chip 20 and an external circuit, and sensing. A sealing member 40 that seals a part of the sensor chip 20 and supports it in a cantilever manner while exposing the portion 21 is provided.

  The substrate 10 is composed of islands of lead frames having islands formed by etching or pressing a plate material such as Cu or Fe, and connecting leads, and has a rectangular plate shape.

  In the present embodiment, the sensor chip 20 is configured by joining the sensor unit 50 and the cap unit 70, and has a rectangular parallelepiped shape with one direction (the left-right direction in FIG. 1) as the longitudinal direction. Then, one end portion (the end portion on the right side of the paper surface in FIG. 1) is joined to the substrate 10 and sealed by the sealing member 40 so that the sensing portion 21 protrudes from the substrate 10.

  As shown in FIGS. 2C and 3, the sensor unit 50 according to the present embodiment includes an SOI substrate having a rectangular plate shape in which a support substrate 51, a buried insulating film 52, and a semiconductor layer 53 are sequentially stacked. 54. Although FIG. 2C is a side view, the buried insulating film 52 and an insulating film 72 described later are hatched.

  As shown in FIG. 3, the support substrate 51 is formed with a recess 55 having a rectangular cross section reaching the embedded insulating film 52. Thus, a thin diaphragm 56 is formed by the embedded insulating film 52 and the semiconductor layer 53 that form the bottom surface of the recess 55.

  In the portion of the semiconductor layer 53 that forms the diaphragm 56, four gauge resistors 57 (only two are shown in FIG. 3) whose resistance value varies with pressure are formed to form a bridge circuit. That is, when a pressure is applied to the diaphragm 56, the sensor unit 50 of the present embodiment changes the resistance value of the gauge resistor 57, changes the voltage of the bridge circuit, and outputs a sensor signal in accordance with the change of the voltage. It is supposed to be.

  In the present embodiment, the sensing unit 21 is configured by the diaphragm 56 and the gauge resistor 57.

  Furthermore, a wiring layer 58 is formed on one end side of the semiconductor layer 53 with respect to the portion constituting the diaphragm 56. This wiring layer 58 is connected to each gauge resistor 57 in a cross section different from FIG. And are electrically connected.

  Further, as shown in FIGS. 2 (b) and 2 (c), one end portion of the support substrate 51 that is sealed by the sealing member 40 has a protruding direction of the sensing portion 21 with respect to the sealing member 40 ( Grooves 59 reaching the buried insulating film 52 are extended along the protruding direction on the side surfaces located at both ends in the direction orthogonal to the left and right direction in FIG. That is, in the cross section shown in FIG. 4, the SOI substrate 54 is T-shaped. In the present embodiment, the groove 59 corresponds to the sensor portion groove of the present invention.

  2B, FIG. 2C, FIG. 3, and FIG. 4, the sensor unit 50 includes a buried insulating film 52 exposed from the groove 59, and a wall surface of the groove 59 (support substrate 51). ), A relaxation member 60 made of PIQ (polyimide / isoindolo / quinazosilion, registered trademark) having a Young's modulus lower than that of the sealing member 40 is disposed on the back surface of the support substrate 51 between the grooves 59. .

  As shown in FIGS. 2C and 3, the cap unit 70 is configured by disposing an insulating film 72 on the surface of the silicon substrate 71, and the insulating film 72 is bonded to the sensor unit 50. In the following description, the surface of the silicon substrate 71 on which the insulating film 72 is formed is referred to as the front surface, and the surface opposite to the surface is referred to as the back surface.

  The silicon substrate 71 has a recess 73 formed at a position facing the sensing unit 21 of the sensor unit 50. The depression 73 constitutes a pressure reference chamber 80 between the cap unit 70 and the sensor unit 50 (the sensing unit 21) when the cap unit 70 is bonded to the sensor unit 50.

  In the present embodiment, as will be described later, since the sensor unit 50 and the cap unit 70 are bonded under vacuum conditions, the pressure reference chamber 80 is set to a vacuum pressure.

The insulating film 72 is for insulating the sensor unit 50 and the silicon substrate 71 and is made of an insulating material such as SiO _{2. The} insulating film 72 is formed on the entire surface of the silicon substrate 71 facing the sensor unit 50. . Of course, it is also formed on the surface of the recess 73.

  Further, as shown in FIGS. 2A and 2C, one end portion of the silicon substrate 71 sealed by the sealing member 40 has a portion sealed by the sealing member 40. Grooves 74 reaching the insulating film 72 are extended along the protruding direction on the side surfaces located at both ends in the direction orthogonal to the protruding direction. That is, in the cross section shown in FIG. 4, the silicon substrate 71 and the insulating film 72 have an inverted T shape. In the present embodiment, the groove 74 corresponds to the groove for the joining member of the present invention.

  Further, as shown in FIG. 3, the cap portion 70 is connected to the sensor portion 50 and the cap portion in an area where the groove 74 is not formed, which is one end portion sealed by the sealing member 40. Four through electrode portions 75 penetrating in the stacking direction with the portion 70 are formed.

  Each through-electrode portion 75 penetrates the silicon substrate 71 and the insulating film 72 and exposes the wiring layer 58, and the insulating film 75b formed from the wall surface of the hole portion 75a to the back surface of the silicon substrate 71. And disposed on the insulating film 75b formed on the wall surface of the hole 75a, filling the hole 75a, and having one end connected to the wiring layer 58 and the other end of the through electrode 75c. The connection portion 75d is disposed on the insulating film 75b formed on the back surface side of the silicon substrate 71.

  For example, TEOS or the like is used as the insulating film 75b, and Al or the like is used as the through electrode 75c and the connection portion 75d, for example.

  Further, a silicon nitride film 76 is formed on the cap portion 70 so as to cover the insulating film 75b and the connection portion 75d.

  Further, as shown in FIG. 2A, FIG. 2C, FIG. 3 and FIG. 4, the cap portion 70 has an insulating film 72 exposed from the groove 74 and a wall surface of the groove 74 (side surface of the silicon substrate 71). ), A relaxation member 77 made of PIQ or the like having a Young's modulus lower than that of the sealing member 40 is disposed on the back surface of the silicon substrate 71 between the grooves 74.

  The silicon nitride film 76 and the relaxing member 77 are formed with contact holes 76a and 77a that expose a part of the connection portion 75d. The connection portion 75d and the connection terminal 30 are connected to the contact holes 76a and 77a. The electrical connection can be achieved.

  In the present embodiment, the groove 59 formed in the sensor unit 50 and the groove 74 formed in the cap unit 70 have the same shape, and the groove 59 and the groove 74 are formed of the embedded insulating film 52 and the semiconductor layer 53. The insulating film 72 is symmetrical.

  The above is the configuration of the sensor chip 20 in the present embodiment. In the present embodiment, the surface of the silicon substrate 71 opposite to the insulating film 72 side corresponds to one surface of the sensor chip of the present invention, and the surface of the support substrate 51 opposite to the buried insulating film 52 side. This corresponds to the other surface of the sensor chip of the present invention.

  As shown in FIG. 1, a plurality of connection terminals 30 are arranged separately from the substrate 10 outside the end portion of the substrate 10. In the present embodiment, these connection terminals 30 are constituted by connection leads of a lead frame, and are electrically connected to the connection portions 75d exposed from the contact holes 76a and 77a via wires 90 and the like.

  Although not particularly illustrated, a circuit chip may be connected between the sensor chip 20 and the connection terminal 30, and a sensor signal may be output from the connection terminal 30 after a predetermined calculation is performed by the circuit chip.

  The sealing member 40 is made of a general mold resin such as an epoxy resin, and seals one end of the sensor chip 20 and cantileverly supports it while exposing the outer lead portions of the sensing portion 21 and the connection terminal 30. ing. In the present embodiment, the sealing member 40 seals one end portion of the sensor chip 20 so that the end portion on the other end side of the sensor chip 20 coincides with the relaxing members 60 and 77.

  The above is the configuration of the physical quantity sensor in the present embodiment. Next, a method for manufacturing the physical quantity sensor will be described with reference to FIGS.

  First, as shown in FIG. 5 (a), an SOI wafer 54a having a plurality of chip formation regions is formed by laminating a wafer-like support substrate 51a, a buried insulating film 52a, and an n-type semiconductor layer 53a. prepare. Then, a p-type impurity such as boron is ion-implanted into the semiconductor layer 53a and thermally diffused, thereby forming a gauge resistor 57 and a wiring layer 58 in each chip formation region.

Also, a silicon substrate 71a having the same size as the SOI wafer 54a and constituting the cap unit 70 is prepared. Next, the depression 73 is formed by etching a part of the surface of the silicon substrate 71a that faces the sensing unit 21. Thereafter, the surface of the silicon substrate 71a by thermal oxidation method or the CVD method or the like to form an insulating film 72a made of SiO ₂ or the like constituting the cap wafer 70a.

  In this embodiment, the SOI wafer 54a corresponds to the sensor unit wafer of the present invention, and the cap wafer 70a corresponds to the bonding member wafer of the present invention. Further, although not particularly limited, as the support substrate 51a and the silicon substrate 71a, for example, those having a thickness of about 725 μm are used.

  Then, the SOI wafer 54a and the cap wafer 70a are bonded together to form the sensor chip wafer 100. Although not particularly limited, the SOI wafer 54a and the cap wafer 70a can be bonded together as follows.

That is, first, the SOI wafer 54a and the cap wafer 70a are placed in a vacuum apparatus. Then, the surface (bonding surface) of the SOI wafer 54a and the surface (bonding surface) of the cap wafer 70a are irradiated with N ₂ plasma, O ₂ plasma, or Ar ion beam, and each surface (bonding) of the semiconductor layer 53a and the insulating film 72a is bonded. The surface).

  Next, alignment is performed by an infrared microscope or the like using alignment marks provided on the SOI wafer 54a and the cap wafer 70a in a vacuum apparatus, and the SOI wafer 54a and the cap wafer 70a are so-called at a low temperature of room temperature to 550 ° C. Bond together by direct bonding. As a result, a sensor chip wafer 100 is formed in each chip formation region, which is sealed by the SOI substrate 54 obtained by dividing the SOI wafer 54a into chips and the recess 73, and the pressure reference chamber 80 is evacuated. Is done.

  FIGS. 5, 6A, and 6B show the wafer state, but in order to make it easier to understand, the portions constituting the sensor unit 50 when divided into chips are shown. The reference numeral of the sensor unit 50 is attached, and the part of the cap part 70 is attached with the reference numeral of the cap unit 70. Hereinafter, one surface of the cap wafer 70a opposite to the SOI wafer 54a will be described as the back surface of the cap wafer 70a, and one surface of the SOI wafer 54a opposite to the cap wafer 70a will be described as the back surface of the SOI wafer 54a.

  Subsequently, as shown in FIG. 5B, the silicon substrate 71a is ground and polished from the back surface of the cap wafer 70a to reduce the thickness of the cap wafer 70a to about 100 μm. This is to reduce the process time by reducing the etching amount when forming the hole 75a and the groove 74 described later.

  Then, a mask in which a predetermined opening region is formed is arranged on the back surface of the cap wafer 70a, and dry etching or the like is performed to remove the silicon substrate 71a at a location corresponding to the wiring layer 58 of the SOI wafer 54a. A hole 75a is formed.

  Further, as shown in FIG. 7A, in this embodiment, simultaneously with the step of forming the hole 75a, each chip formation region is divided into chips and then sealed by the sealing member 40. Grooves 74 are formed in portions located at both ends in the direction orthogonal to the protruding direction in the one end portion.

  Since the groove 74 is formed simultaneously with the hole 75a, the groove 74 has the same depth as the hole 75a and reaches the insulating film 72a. Each chip formation region shown in FIG. 7 is partitioned by dicing lines 81.

  Next, as shown in FIG. 5C, an insulating film 75b such as TEOS is formed from the back surface of the cap wafer 70a. Thereafter, the insulating film 75b formed on the back surface of the cap wafer 70a is appropriately patterned, and the insulating film 75b and the insulating film 72a disposed at the bottom of each hole 75a are removed to remove the wiring layer 58 from each hole 75a. Expose.

  Subsequently, a metal such as Al or Al-Si is formed on the back surface of the cap wafer 70a by sputtering or vapor deposition to form a through electrode 75c in the hole 75a, and the through electrode 75c and the wiring layer 58 are formed. Connect electrically. Then, a metal film formed on the back surface of the cap wafer 70a is appropriately patterned to form a connection portion 75d that is electrically connected to the through electrode 75c. Thereby, the penetration electrode part 75 is formed in each chip | tip formation area.

  Thereafter, as shown in FIGS. 5D and 7B, a silicon nitride film 76 is formed from the back surface of the cap wafer 70a by a plasma CVD method or the like, and then patterned. Further, after PIQ or the like is formed by vapor deposition, sputtering, spin coating or the like, patterning is performed, and the insulating film 72a exposed from the groove 74, the wall surface of the groove 74 (side surface of the silicon substrate 71a), and the back surface of the silicon substrate 71a are patterned. A relaxation member 77 is formed in a portion sandwiched by the grooves 74. Then, contact holes 76 a and 77 a are formed in the silicon nitride film 76 and the relaxing member 77.

  Next, as shown in FIG. 6A, the support substrate 51a is ground and polished from the back surface of the SOI wafer 54a to reduce the thickness of the support substrate 51a to about 300 μm. This is to reduce the process time for forming the recess 55 and the groove 59 described later.

  And the recessed part 55 is formed in each chip | tip formation area of the support substrate 51a. Thereby, the diaphragm 56 is formed in each chip formation region, and the sensing unit 21 including the diaphragm 56 and the gauge resistor 57 is formed.

  Further, as shown in FIG. 8A, in this embodiment, simultaneously with the step of forming the recess 55, the chip forming region is divided into chips and then sealed by the sealing member 40 at the same time. Grooves 59 are formed at portions located at both ends in the direction orthogonal to the protruding direction at one end.

  Since the trench 59 is formed at the same time as the recess 55, it has the same depth as the recess 55 and reaches the buried insulating film 52a. Each chip formation region shown in FIG. 8 is partitioned by dicing lines 81.

  Thereafter, as shown in FIG. 6B, a PIQ or the like is formed from the back surface of the SOI wafer 54a by vapor deposition, sputtering, spin coating or the like, and then patterned, and the buried insulating film 52a exposed from the trench 59 is exposed. The relaxation member 77 is disposed on the side surface of the support substrate 51a (the wall surface of the groove 59) and the back surface of the support substrate 51a between the grooves 59.

  Next, as shown in FIG. 6C, the sensor chip 20 is formed by dividing the sensor chip wafer 100 into chips along the dicing line 81. Accordingly, grooves 59 and 74 are formed on the side surfaces located at both ends in the direction orthogonal to the protruding direction among the one end portion sealed by the sealing member 40, and the plurality of relaxation members 60 and 77 are arranged. The sensor chip 20 is manufactured at the same time.

  After that, it manufactures by performing the process similar to the conventional manufacturing method. Briefly, a lead frame in which the substrate 10 and the connection terminals 30 are coupled to the frame portion and integrated is prepared. In addition, the board | substrate 10 and the connection terminal 30 are isolate | separated by cutting a frame part after resin sealing.

  Then, the sensor chip 20 is mounted on the substrate 10 via a die bond material so that the sensing unit 21 protrudes from the substrate 10, and the connection portion 75 d and the connection terminal 30 are electrically connected via the wire 90 or the like.

  Subsequently, the substrate 10, the sensor chip 20, the connection terminal 30, and the wire 90 are sealed with the sealing member 40 while exposing the sensing portion 21 and the outer lead portion of the connection terminal 30. Thereafter, the physical quantity sensor is manufactured by cutting a frame portion connecting the substrate 10 and the connection terminal 30.

  As described above, in this embodiment, one end of the sensor chip 20 sealed by the sealing member 40 has grooves 59 on the side surfaces located at both ends in the direction orthogonal to the protruding direction of the sensing unit 21. 74 is formed, and the relaxation members 60 and 77 are arranged in the region including the grooves 59 and 74. For this reason, compared with a pressure sensor in which one end of the sensor chip 20 is directly sealed by the sealing member 40, the stress applied from the sealing member 40 to the sensor chip 20 can be relaxed, and the detection accuracy is improved. It can suppress that it falls.

  In addition, since the relaxation members 60 and 77 are arranged in this way and the stress applied from the sealing member 40 to the sensor chip 20 can be relaxed, the sealing member 40 is peeled off from the sensor chip 20. It can also be suppressed.

  Furthermore, in this embodiment, the grooves 59 and 74 are formed in the wafer state, and the relaxation members 60 and 77 are disposed. For this reason, a plurality of sensor chips 20 on which the relaxing members 60 and 77 are arranged can be manufactured at the same time. That is, for example, after dividing into chips, the manufacturing process can be simplified as compared with the method in which the relaxation member is arranged for each chip.

  Further, since the hole 75a and the groove 74 are formed at the same time, and the concave portion 55 and the groove 59 are formed at the same time, the manufacturing process can be reduced.

(Other embodiments)
In the first embodiment, the grooves 59 and 74 may be formed by wet etching. In this case, since the wall surfaces of the grooves 59 and 74 are tapered, the relaxation members 60 and 77 can be easily disposed on the wall surfaces of the grooves 59 and 74 when the PIQ or the like is formed.

  In the first embodiment, a high-concentration n-type region is formed by ion-implanting n-type impurities such as phosphorus into the n-type semiconductor layer 53a and thermally diffusing, and the high-concentration n-type is formed in the cap portion 70. A through electrode portion that is electrically connected to the region may be formed. According to this, by applying a predetermined voltage to the high-concentration n-type region, a reverse bias can be applied to the pn junction constituted by the n-type semiconductor layer 53a and the p-type gauge resistor 57, The occurrence of leak can be suppressed.

  Furthermore, in the first embodiment, separate masks may be prepared in the step of forming the hole 75a and the step of forming the groove 74, and the hole 75a and the groove 74 may be formed in separate steps. Similarly, separate masks may be prepared in the step of forming the recess 55 and the step of forming the groove 59, and the recess 55 and the groove 59 may be formed in separate steps.

  In this case, the depth of the grooves 59 and 74 can be changed as appropriate, and the groove 59 can be formed to penetrate the SOI wafer 54a, and the groove 74 can be formed to penetrate the cap wafer 70a. That is, the groove 59 and the groove 74 can be communicated with each other. According to this, since the relaxation members 60 and 77 can be disposed on the entire side surface of the sensor chip 20 that is sealed with the sealing member 40, the stress can be further relaxed.

  And in the said 1st Embodiment, the edge part by the side of the other end part of the sealing member 40 and the edge part by the side of the other end part of the relaxation members 60 and 77 do not need to correspond. That is, as shown in FIG. 9, the relaxation members 60 and 77 may be completely sealed by the sealing member 40. Further, although not particularly illustrated, a part of the relaxing members 60 and 77 may be exposed from the sealing member 40. That is, the grooves 59 and 74 may be formed longer than a portion sealed by the sealing member 40 in the sensor chip 20 or a portion sealed by the sealing member 40 in the sensor chip 20. It may be formed shorter.

  Furthermore, in the first embodiment, the sensor unit 50 may be formed of a silicon substrate or the like.

  In the first embodiment, the physical quantity sensor using the sensor chip 20 in which the cap unit 70 is bonded to the one surface on which the sensing unit 21 is formed has been described. However, the configuration of the sensor chip 20 is not limited thereto. For example, the sensor chip 20 shown in FIG. 10 can also be used.

  Note that although FIG. 10 illustrates an example in which the sensor unit 50 is formed of a silicon substrate, an SOI substrate or the like can be used as appropriate. In FIG. 10, the gauge resistor 57 and the wiring layer 58 are omitted.

  For example, as shown in FIG. 10A, the sensor chip 20 may be configured by a sensor unit 50 having a recess 55 having a rectangular cross section on the back surface and a pedestal 110 bonded to the back surface. Good. Moreover, as shown in FIG. 10B, the recess 55 may have a trapezoidal cross section.

  Further, as shown in FIG. 10C, the silicon substrate constituting the sensor unit 50 is thinned, and a pedestal 110 having a recess 110a formed thereon is bonded to the silicon substrate, so that the silicon substrate faces the recess 110a. The diaphragm 56 may be configured in the region. Further, as shown in FIG. 10 (d), the sensor unit 50 may be formed of only a silicon substrate, and a cavity that forms the pressure reference chamber 80 may be formed inside the silicon substrate. In this silicon substrate, for example, after forming a recess on the surface of the silicon substrate, an epitaxial layer is formed so as to close the recess by LPCVD or the like, whereby the pressure reference chamber 80 (cavity) is configured by the recess. Manufactured.

  In addition, in the sensor chip 20 of FIGS. 10A to 10C, the pedestal 110 corresponds to the joining member of the present invention.

  Further, when a pressure sensor is configured using such a sensor chip 20, the wiring layer 58 is exposed, and therefore the wiring layer 58 and the connection terminal 30 are directly and electrically connected via the wire 90 or the like. Just connect.

  In the first embodiment, the physical quantity sensor including the sensor chip 20 in which the sensing unit 21 for detecting pressure is formed has been described. For example, the sensor chip 20 in which the sensing unit 21 for detecting acceleration and angular velocity is formed. It is also possible to apply the present invention to a physical quantity sensor comprising

DESCRIPTION OF SYMBOLS 20 Sensor chip 21 Sensing part 40 Sealing member 50 Sensor part 59 Groove 60 Mitigation member 70 Cap part 74 Groove 77 Mitigation member

Claims (8)

A sensor chip (20) having a sensing portion (21) having one surface and the other surface opposite to the one surface and outputting a sensor signal according to a physical quantity;
A sealing member (40) that cantilever-supports the sensor chip by sealing a part of the sensor chip while exposing the sensing unit;
In the sensor chip, grooves (59, 74) are formed at both ends in a direction orthogonal to the protruding direction of the sensing unit with respect to the sealing member in a portion sealed by the sealing member, and the region including the groove A physical quantity sensor characterized in that a relaxation member (60, 77) having a Young's modulus lower than that of the sealing member is disposed. The sensor chip includes a sensor unit (50) in which the sensing unit is formed, and a bonding member (70, 110) bonded to the sensor unit,
A sensor part groove is formed as the groove (59) in the sensor part, and a joint member groove is formed as the groove (74) in the joint member,
The physical quantity sensor according to claim 1, wherein the relaxation member is disposed in a region including the sensor portion groove and the bonding member groove.   The physical quantity sensor according to claim 2, wherein the sensor portion groove and the joining member groove are connected to each other.   4. The sensor chip according to claim 1, wherein, in addition to the groove, the relaxation member is disposed on the one surface and the other surface sealed by the sealing member. 5. Physical quantity sensor described in 1. A sensor chip (20) having a sensing unit (21) for outputting a sensor signal corresponding to a physical quantity;
A sealing member (40) that cantilever-supports the sensor chip by sealing a part of the sensor chip while exposing the sensing part (21),
In the sensor chip, grooves (59, 74) are formed at both ends in a direction orthogonal to the protruding direction of the sensing unit with respect to the sealing member in a portion sealed by the sealing member, and the region including the groove In the method of manufacturing a physical quantity sensor, in which the relaxation member (60, 77) having a Young's modulus lower than that of the sealing member is disposed,
Preparing a sensor chip wafer (100) having a plurality of chip formation regions;
In each of the chip formation regions, a step of forming the groove in portions positioned at both ends in a direction orthogonal to the protruding direction among the portions sealed by the sealing member after being divided into chips.
After the step of forming the groove, in each of the chip formation regions, the step of disposing the relaxation member in a region including the groove;
After the step of disposing the relaxation member, dividing the sensor chip wafer into chips along a dicing line, thereby forming a plurality of sensor chips in which the relaxation member is disposed in the region including the groove When,
And a step of sealing a part of the sensor chip with the sealing member while exposing the sensing part. In the step of preparing the sensor chip wafer, a sensor member wafer (54a) on which the sensing unit is formed is prepared by bonding a bonding member wafer (70a),
In the step of forming the groove, a step of forming a groove for the sensor portion as the groove (59) from one surface of the sensor portion wafer opposite to the side to be bonded to the bonding member wafer, and the bonding Forming a bonding member groove as the groove (74) from one surface of the member wafer opposite to the side bonded to the sensor unit wafer;
In the step of disposing the relaxation member, the step of disposing the relaxation member in a region including the sensor portion groove from one surface of the sensor portion wafer, and the bonding member groove from the one surface of the bonding member wafer. The method for manufacturing a physical quantity sensor according to claim 5, wherein the step of arranging the relaxation member in a region is performed.   The method of manufacturing a physical quantity sensor according to claim 6, wherein, in the step of forming the groove, the sensor part groove and the bonding member groove are connected. The method for manufacturing a physical quantity sensor according to claim 5, wherein the step of forming the groove is performed by wet etching.

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