Sensor element and semiconductor wafer

Abstract

A sensor element according to the present invention comprises a substrate and an insulating layer disposed on the substrate. The substrate has a cavity penetrating the substrate in the thickness direction formed therein. The insulating layer has a peripheral part disposed on the part of the substrate around the cavity, and a membrane part disposed on the cavity. In a portion of a peripheral part of the substrate positioned under said peripheral part, a groove is formed so as to extend from the cavity toward an outer periphery part of the substrate. It is possible, by having this configuration, to provide a sensor element for which a possibility of damage due to pressure changes is reduced.

Description

Sensor element and semiconductor wafer

[0001] The present disclosure relates to a sensor element and a semiconductor wafer.

[0002] Japanese Patent Laid-Open Publication No. 2022-183481 (Patent Document 1) discloses a sensor having a membrane portion.

[0003] Japanese Patent Application Laid-Open No. 2022-183481

[0004] [Summary] In a sensor having a membrane, there is a risk that the membrane may be damaged by thermal stress. In the above-mentioned Japanese Patent Application Laid-Open No. 2022-183481, through holes are provided in the membrane to relieve the thermal stress.

[0005] For example, in the case of a sensor without a through-hole, the cavity in the sensor's membrane is sealed at 1 atmosphere during manufacturing when the sensor is mounted on a circuit board. For example, in a high-pressure environment, changes in external air pressure can disrupt the pressure balance, potentially damaging the membrane. In such cases, a through-hole in the membrane is effective.

[0006] However, the membrane is a thin film, and providing through holes reduces its strength, making it vulnerable to mechanical shocks, etc. For this reason, there is room for improvement in the structure of the sensor disclosed in JP 2022-183481 A.

[0007] The present disclosure aims to provide a sensor element that is less likely to be damaged by changes in air pressure.

[0008] The present disclosure relates to a sensor element. The sensor element includes a substrate, an insulating film layer disposed on the substrate, and an electrode layer. A cavity penetrating the substrate in the thickness direction is formed in the substrate. The insulating layer has a peripheral portion disposed on the substrate around the cavity, and a membrane portion disposed on the cavity. A groove is formed in a part of the substrate located in the peripheral portion, extending from the cavity toward the outer periphery of the substrate.

[0009] 18 is a top view of the sensor element 100 according to the first embodiment. It is a cross-sectional view taken along the II-II cross section of FIG. 1 . It is a partial side view of the groove G portion of FIG. 1 . It is a top view of a gas sensor, which is an example of a sensor element. It is a cross-sectional view taken along the V-V cross section of FIG. 4 . It is a cross-sectional view showing a structure in which a temperature sensor is provided. It is a process diagram showing a manufacturing process of the sensor element. It is a cross-sectional view for explaining a first insulating layer forming step S2. It is a cross-sectional view for explaining a wiring forming step S3. It is a cross-sectional view for explaining a second insulating layer forming step S4. It is a cross-sectional view for explaining a cavity forming step S5. It is a cross-sectional view of a sensor element according to a modified example of the first embodiment. It is a partial side view of the groove G2 portion of FIG. 12 . It is a top view of a sensor element 101 according to the second embodiment. It is a top view of a sensor element 102 according to the third embodiment. It is a top view of a sensor element 103 according to the fourth embodiment. It is a top view of a sensor element 104 according to the fifth embodiment. It is a top view of a sensor element 105 according to the sixth embodiment. It is a partial side view of the groove G7 portion of FIG. 18 . It is a diagram showing the state of the bonding material according to the sixth embodiment. It is a partial side view of the groove portion of a modified example of the sixth embodiment. 23. A diagram showing the state of a bonding material in a modified example of embodiment 6. A top view of a sensor element 106 in embodiment 7. A cross-sectional view of the XXIV-XXIV cross section in FIG. 23. A diagram for explaining the arrangement of general sensor elements on a wafer. A diagram for explaining the arrangement of sensor elements on a wafer in a studied example. A diagram for explaining the arrangement of sensor elements in embodiment 8.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0011] <Embodiment 1> Fig. 1 is a top view of a sensor element 100 according to embodiment 1. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a partial side view of the groove G in Fig. 1.

[0012] 1 and 2 includes a substrate 10 and an insulating layer 20 disposed on the substrate 10. A cavity C is formed in the substrate 10, penetrating the substrate 10 in the thickness direction. The insulating layer 20 has a peripheral portion 4 disposed on the substrate 10 around the cavity C, and a membrane portion 2 disposed on the cavity C. A groove G extending from the cavity C toward the outer periphery of the substrate 10 is formed in a peripheral portion 6, which is a part of the substrate located in the peripheral portion 4.

[0013] When the substrate 10 is placed on the package substrate 50, the groove G forms a communication path that connects the cavity C and the outer periphery of the substrate 10, as shown in FIGS.

[0014] With this configuration, the inside of the cavity is not sealed, so that it is possible to avoid stress being applied to the membrane portion due to fluctuations in air pressure.

[0015] The sensor is not limited to a specific sensor as long as it has a membrane portion. In the following, an example in which the groove G is applied to a gas sensor will be described, but the structure of the sensor element of this embodiment may also be applied to, for example, a flow sensor, a barometric pressure sensor, a humidity sensor, a temperature sensor, and the like.

[0016] Fig. 4 is a top view of a gas sensor, which is a specific example of a sensor element, and Fig. 5 is a cross-sectional view taken along the line VV in Fig. 4.

[0017] 4 and 5, the wiring 30 is indicated by a dotted line. As shown in FIGS. 4 and 5, the sensor element 100, which is a gas sensor, includes a substrate 10, an insulating layer 20, and wiring 30.

[0018] The substrate 10 has a first main surface F1 and a second main surface F2. The first main surface F1 and the second main surface F2 are end surfaces of the substrate 10 in the thickness direction. The second main surface F2 is the surface opposite to the first main surface F1. A cavity C is formed in the substrate 10. The cavity C penetrates the substrate 10 along the thickness direction of the substrate 10. The cavity C has a rectangular shape in plan view (when viewed along the thickness direction of the substrate 10 from the first main surface F1 side). The substrate 10 is formed of, for example, single crystal silicon. Note that the shape of the cavity C in plan view is not limited to a rectangular shape and may be a circular shape, a polygonal shape, or the like.

[0019] The insulating layer 20 is disposed on the substrate 10. More specifically, the insulating layer 20 is disposed on the first main surface F1. The insulating layer 20 includes, for example, a first layer 21, a second layer 22, a third layer 23, and a fourth layer 24.

[0020] The first layer 21 is disposed on the substrate 10 (first main surface F1). The first layer 21 is formed of, for example, silicon oxide. The second layer 22 is disposed on the first layer 21. The second layer 22 is formed of, for example, silicon nitride. The third layer 23 is disposed on the second layer 22. The third layer 23 is formed of, for example, silicon oxide. The fourth layer 24 is disposed on the third layer 23. The fourth layer 24 is formed of, for example, silicon oxide.

[0021] The portion of the insulating layer 20 that is disposed on the substrate 10 around the cavity C is referred to as a peripheral portion 4. The portion of the insulating layer 20 that is above the cavity C is referred to as a membrane portion 2. The membrane portion 2 is connected to the peripheral portion 4. The membrane portion 2 is supported above the cavity C by the peripheral portion 4. The portion of the peripheral portion 4 that is located above the groove G is referred to as a peripheral portion 6.

[0022] The wiring 30 is disposed in the insulating layer 20. More specifically, the wiring 30 is disposed on the third layer 23 and covered by the fourth layer 24. The periphery of the wiring 30 is covered by a barrier layer 31. The barrier layer 31 ensures adhesion between the insulating layer 20 and the wiring 30. The wiring 30 is made of, for example, platinum. The barrier layer 31 is made of, for example, titanium oxide. The portion of the barrier layer 31 disposed on the third layer 23 is referred to as a first portion 31a, and the portion of the barrier layer 31 covering the wiring 30 is referred to as a second portion 31b.

[0023] The wiring 30 has a heater portion 30a, an end portion 30b, and a connection portion 30c. The heater portion 30a is formed by meandering the wiring 30. The heater portion 30a is disposed in the membrane portion 2. The end portion 30b is disposed in the peripheral portion 4. The connection portion 30c connects the heater portion 30a and the end portion 30b.

[0024] A pad portion 30d is disposed on the insulating layer 20. The pad portion 30d is electrically connected to the end portion 30b through an opening (not shown) formed in the insulating layer 20 (fourth layer 24) so ​​as to expose the end portion 30b.

[0025] (Operation of the sensor element 100 according to the embodiment) The operation of the sensor element 100 will be described below. Here, the operation of the sensor element 100 will be described using the case of detecting hydrogen gas in the detection target gas as an example.

[0026] When a current flows through the wiring 30, the heater section 30a generates heat by resistance. That is, the temperature of the heater section 30a (heater temperature) changes depending on the type (thermal conductivity) of gas present in the atmosphere in which the heater section 30a is placed. For example, by providing a temperature sensor that detects the heater temperature in the membrane section, changes in the heater temperature can be observed.

[0027] Fig. 6 is a diagram showing an example of a cross-sectional structure when a heater is provided. In addition to the cross-sectional structure shown in Fig. 5, Fig. 6 shows a wiring 40 serving as a temperature sensor, an insulating layer 41 made of silicon oxide, an insulating layer 42 made of silicon nitride, and an insulating layer 43 made of silicon oxide. The wiring 40 is surrounded by a barrier layer, similar to the wiring 30.

[0028] For example, since the thermal conductivity of hydrogen is nearly one order of magnitude higher than that of other gases, the sensor element 100 equipped with a microheater that generates a difference in the amount of heat dissipation is used as a hydrogen sensor.

[0029] (Method for manufacturing the sensor element 100 according to the embodiment) A method for manufacturing the sensor element 100 will be described below.

[0030] 7 is a process diagram showing the manufacturing process of the sensor. As shown in Fig. 7, the manufacturing method of the sensor element 100 includes a preparation step S1, a first insulating layer forming step S2, a wiring forming step S3, a second insulating layer forming step S4, and a cavity forming step S5.

[0031] In the preparation step S1, a substrate 10 is prepared. Note that the substrate 10 prepared in the preparation step S1 does not have a cavity C formed therein.

[0032] 8 is a cross-sectional view illustrating the first insulating layer forming step S2. As shown in FIG. 8, in the first insulating layer forming step S2, a first layer 21, a second layer 22, and a third layer 23 are formed in sequence. The first layer 21, the second layer 22, and the third layer 23 are formed by, for example, a chemical vapor deposition (CVD) method.

[0033] 9 is a cross-sectional view illustrating the wiring formation step S3. As shown in FIG. 9, in the wiring formation step S3, wiring 30 and barrier layer 31 are formed. In the wiring formation step S3, first, a first portion 31a is formed. The first portion 31a is formed by depositing and patterning a material constituting the barrier layer 31. This deposition is performed using, for example, a sputtering method. This patterning is performed by forming a mask pattern using photolithography and etching using the formed mask pattern.

[0034] Secondly, in the wiring formation step S3, the wiring 30 is formed. The wiring 30 is formed by depositing and patterning a material constituting the wiring 30. This deposition is performed using, for example, a sputtering method. This patterning is performed by forming a mask pattern using photolithography and etching using the formed mask pattern. Thirdly, in the wiring formation step S3, the second portion 31b is formed. The second portion 31b is formed by depositing and patterning a material constituting the barrier layer 31. This deposition is performed using, for example, a sputtering method. This patterning is performed by forming a mask pattern using photolithography and etching using the formed mask pattern.

[0035] 10 is a cross-sectional view illustrating the second insulating layer forming step S4. As shown in FIG. 10, in the second insulating layer forming step S4, a fourth layer 24 is formed. The fourth layer 24 is formed by using, for example, a CVD method.

[0036] 11 is a cross-sectional view illustrating the cavity forming step S5. In the cavity forming step S5, the cavity C and the groove G are formed. The cavity C and the groove G are formed by, for example, anisotropic dry etching. In this manner, the sensor element 100 having the structure shown in FIGS. 4 and 5 is formed.

[0037] As described above, the sensor element of the first embodiment has the groove G to form a communication path between the cavity C and the external space. This prevents a pressure difference from occurring between the inside of the cavity C and the external atmosphere. This prevents the membrane from being damaged by a pressure difference. Furthermore, since no through-holes are provided in the thin membrane, a decrease in the strength of the membrane can be avoided. Furthermore, the groove G is not located on one side of the outer periphery where the pad portion 30d is provided. This prevents the groove from being blocked by a potting material such as resin that protects the bonding wires and pads from the external air.

[0038] The sensor element of the first embodiment can be suitably used, for example, when detecting the gas concentration in a pipeline where the pressure is high.

[0039] Fig. 12 is a cross-sectional view of a sensor element according to a modification of embodiment 1. Fig. 13 is a partial side view of the groove G2 portion of Fig. 12.

[0040] 12, the sensor element of the modified example of the first embodiment has a groove G2 formed in the substrate 10. The groove G2 is characterized in that the depth D2 is shallower than the depth D1 of the cavity C.

[0041] In FIG. 3, the depth of groove G is the same as the depth of cavity C, but by making the width of groove G2 narrower than in FIG. 3, the etching rate can be made slightly slower than that of cavity C, and the portion of substrate 10 in contact with insulating layer 20 can be left as shown in FIG. 13.

[0042] This makes it possible to secure a communication path between the inside and outside of the cavity C while improving the strength of the sensor.

[0043] <Embodiment 2> Fig. 14 is a top view of a sensor element 101 according to embodiment 2. In embodiment 2, as shown in Fig. 14, a sensor element 101 is shown in which grooves G3 are provided in a direction intersecting the four sides of the rectangle of the sensor substrate, i.e., in an oblique direction. Even when grooves of this shape are provided, the same effects as in embodiment 1 can be achieved. Note that in embodiment 2 as well, the depth of groove G3 may be shallower than the depth of cavity C, as shown in Figs. 12 and 13.

[0044] Furthermore, by forming the groove G3 in an oblique direction, cracks such as those described later with reference to FIG. 25 can be made less likely to occur.

[0045] <Embodiment 3> Fig. 15 is a top view of a sensor element 102 according to embodiment 3. In embodiment 3, as shown in Fig. 15, the groove G4 is not straight but bent. That is, the communication path that connects the cavity C formed in the sensor element 102 to the outside has a bent portion (groove G4). Even when a groove having such a shape is provided, the same effect as in embodiment 1 can be achieved. Note that, in embodiment 3 as well, the depth of the groove G3 may be shallower than the depth of the cavity C, as shown in Figs. 12 and 13.

[0046] Furthermore, by forming the groove G4 in a bent shape, cracks such as those described later with reference to FIG. 25 can be made less likely to occur.

[0047] <Fourth Embodiment> Fig. 16 is a top view of a sensor element 103 according to a fourth embodiment. In the fourth embodiment, as shown in Fig. 16, the groove G5 is curved rather than straight. That is, the communication path that connects the cavity C formed in the sensor element 102 to the outside has a curved portion (groove G5). Even when a groove having such a shape is provided, the same effect as in the first embodiment can be achieved. Note that, in the fourth embodiment, the depth of the groove G5 may be shallower than the depth of the cavity C, as shown in Figs. 12 and 13.

[0048] Furthermore, by forming the groove G5 in a curved shape, cracks such as those described later with reference to FIG. 25 can be made less likely to occur.

[0049] <Embodiment 5> Figure 17 is a top view of a sensor element 104 according to embodiment 5. In embodiment 5, as shown in Figure 17, multiple grooves are provided, such as grooves G6A and G6B. Providing grooves of this shape can achieve the same effect as embodiment 1. Furthermore, providing multiple grooves allows for smoother gas exchange within the cavity compared to a single groove, and is more effective in preventing damage to the cavity. Note that, in embodiment 5 as well, the depth of grooves G6A and G6B may be shallower than the depth of cavity C, as shown in Figures 12 and 13.

[0050] Sixth Embodiment FIG. 18 is a top view of a sensor element 105 according to a sixth embodiment. FIG. 19 is a partial side view of the groove G7 portion of FIG. 18. In the sensor element 105, as shown in FIGS. 18-20, the multiple communication paths G7 are formed by a main groove G7A and auxiliary grooves G7B and G7C that are spaced apart from the main groove G7A and shallower than the main groove G7A in the thickness direction of the substrate. The auxiliary grooves G7B and G7C serve to absorb excess bonding material when bonding the substrate 10 and the package substrate 50 together with the bonding material. By making the widths of the auxiliary grooves G7B and G7C narrower than the width of the main groove G7A, the etching rate is slowed, and the depths of the auxiliary grooves G7B and G7C can be made shallower than the depth of the main groove G7A.

[0051] FIG. 20 is a diagram showing the state of the bonding material in the sixth embodiment. The substrate 10 and the package substrate 50 are bonded together by the bonding material 51. The amount of bonding material 51 applied is often somewhat excessive. In this case, for example, if the groove width is narrow and the groove depth is shallow as shown in FIG. 13, excess bonding material 51 may enter the groove and block the communication path. However, if auxiliary grooves G7B and G7C are disposed on both sides of the main groove G7A, the auxiliary grooves G7B and G7C can absorb excess bonding material 51 near the main groove G7A, thereby preventing the communication path formed by the main groove G7A from being completely blocked to some extent.

[0052] Therefore, by using the configuration shown in Figures 18 and 19, the depth of the groove can be made shallower, maintaining the strength of the substrate portion while reducing the possibility of the main groove being blocked by excess bonding material.

[0053] FIG. 21 is a partial side view of a groove portion of a modified example of the sixth embodiment. FIG. 22 is a diagram showing the state of the bonding material of a modified example of the sixth embodiment. In the modified example of the sixth embodiment, as shown in FIGS. 21 and 22, the groove G8 has a stepped shape with one or more steps in the thickness direction. In this case, the number of grooves is one, but even by using the configuration shown in FIG. 21, the groove depth can be made shallower to maintain the strength of the substrate portion, while reducing the possibility of the main groove being blocked by excess bonding material as shown in FIG. 22. For example, by partially forming an insulating film (such as a silicon oxide film) in the groove portion before forming the cavity, the amount of etching other than the center of the groove can be reduced, thereby creating a stepped shape.

[0054] Seventh Embodiment Fig. 23 is a top view of a sensor element 106 according to a seventh embodiment. Fig. 24 is a cross-sectional view taken along the line XXIV-XXIV in Fig. 23. In the sensor element 106, as shown in Figs. 23 and 24, the substrate 10 has a first main surface F1 on the membrane portion side and a second main surface F2 in contact with the package substrate 50, and a through hole H is formed in the substrate 10 and the insulating layer 20, penetrating from the first main surface F1 toward the second main surface F2 and communicating with the groove G9.

[0055] This configuration can prevent stress from being applied to the membrane due to changes in atmospheric pressure. Furthermore, by providing through holes in the peripheral portion 4, the strength of the membrane can be reduced more than by providing through holes in the membrane portion 2.

[0056] Eighth Embodiment Fig. 25 is a diagram for explaining a typical arrangement of sensor elements on a wafer. On a semiconductor wafer 200, regions 201 in which sensors are arranged in rows and columns are arranged without any gaps on the semiconductor wafer 200. The sensor manufacturing process described with reference to Figs. 7 to 11 is carried out on the semiconductor wafer 200, and then the semiconductor wafer 200 is cut into individual sensor element chips.

[0057] Fig. 26 is a diagram for explaining the arrangement of sensor elements on a wafer in the study example. For example, as shown in area 201A in Fig. 26, if sensor elements 100 having grooves formed in the same direction are arranged in the same orientation, the groove portions, which reduce strength, will be aligned in a straight line, and therefore, if an impact is applied to the wafer during the manufacturing process after the grooves are formed or during the process of separating the sensor elements into individual chips, the wafer may crack along the line BL.

[0058] Fig. 27 is a diagram for explaining the arrangement of the sensor element according to the embodiment 8. In the arrangement of the region 201B shown in Fig. 27, several measures are taken to make cracks less likely to occur.

[0059] For example, the sensor element 101 has a groove oriented in an oblique direction, and even if the sensor elements 101 are repeatedly arranged in the same direction, a straight line prone to cracking as shown in FIG. 26 does not occur.

[0060] For example, when the substrate 10 is a silicon substrate, the plane (cleavage plane) where cracks are likely to occur is the (111) plane or the (110) plane. Therefore, if the groove direction is along these planes, cracks are likely to occur. Therefore, it is preferable that the groove direction is oblique and intersects with the (111) plane or the (110) plane.

[0061] Furthermore, even if a sensor element has a groove oriented in the same direction as the row or column direction of the sensor element arrangement, such as sensor element 100, it is not arranged continuously, but is arranged mixed with sensor element 101 having a diagonal groove and sensor element 102 having a bent portion in the groove, thereby preventing the formation of straight lines that are prone to cracking as shown in Figure 26.

[0062] Furthermore, even if the sensor elements have grooves of the same shape, by arranging them in various directions as in sensor elements 101, 101A, 101B, 101C, and 101D in Figure 27, the straight lines that are prone to cracking as shown in Figure 26 will not occur.

[0063] Furthermore, by arranging elements without grooves as dummy elements 100D that are not used as sensor elements in part of the matrix arrangement, the easily broken straight lines shown in FIG. 26 do not occur.

[0064] These techniques may be implemented individually or in combination as shown in FIG.

[0065] By adopting the above-described arrangement, it is possible to reduce the possibility of unintended cracks occurring in the wafer state.

[0066] [Note] The present embodiment will be summarized below with reference to the drawings again.

[0067] (Item 1) The present disclosure relates to a sensor element. A sensor element 100 shown in Figures 1 and 2 includes a substrate 10 and an insulating layer 20 disposed on the substrate 10. A cavity C is formed in the substrate 10, penetrating the substrate 10 in the thickness direction. The insulating layer 20 has a peripheral portion 4 disposed on the substrate 10 around the cavity C, and a membrane portion 2 disposed on the cavity C. A groove G is formed in a peripheral portion 6, a part of the substrate located in the peripheral portion 4, extending from the cavity C toward the outer periphery of the substrate 10.

[0068] By adopting such a configuration, it is possible to prevent stress from being applied to the membrane portion due to fluctuations in atmospheric pressure.

[0069] (Item 2) In the sensor element described in item 1, when the substrate 10 is placed on the package substrate 50, the groove G forms one or more communication paths that connect the cavity C to the outer periphery of the substrate 10.

[0070] By adopting such a configuration, it is possible to prevent stress from being applied to the membrane portion due to fluctuations in atmospheric pressure.

[0071] (Item 3) In the sensor element described in item 2, as shown in Figures 15 and 16, when the substrate 10 is viewed from the first main surface F1 side on the membrane portion side to the second main surface F2 side that abuts the package substrate 50, the communication path has a curved portion (groove G5) or a bent portion (groove G4).

[0072] By adopting such a configuration, it is possible to prevent stress from being applied to the membrane portion due to fluctuations in atmospheric pressure.

[0073] (4) In the sensor element described in 2, as shown in Figures 23 and 24, the substrate 10 has a first main surface F1 on the membrane portion side and a second main surface F2 abutting the package substrate 50, and a through hole H is formed in the substrate 10 and the insulating layer 20, penetrating from the first main surface F1 side toward the second main surface F2 and communicating with the groove G9.

[0074] By adopting such a configuration, it is possible to prevent stress from being applied to the membrane portion due to fluctuations in atmospheric pressure.

[0075] (Item 5) In the sensor element described in item 2, as shown in Figures 18-20, the multiple communication paths G7 are formed by a main groove G7A and auxiliary grooves G7B and G7C that are spaced apart from the main groove G7A and shallower than the main groove G7A in the thickness direction of the substrate.

[0076] This configuration reduces the possibility that the main groove will be blocked by excess bonding material.

[0077] (Item 6) In the sensor element described in item 1, as shown in FIGS. 21 and 22, the groove G8 has a stepped shape with one or more steps in the thickness direction.

[0078] This configuration reduces the possibility that the groove will be blocked by excess bonding material.

[0079] (Item 7) In the sensor element described in item 1, when the substrate 10 is placed on the package substrate 50, as shown in Figures 12 and 13, the substrate 10 has a first main surface F1 on which the insulating layer 20 is formed and a second main surface F2 that abuts the package substrate 50, and the depth D2 of the groove G2 from the second main surface F2 in the thickness direction is shallower than the depth D1 of the cavity C.

[0080] By adopting such a configuration, the strength of the substrate can be increased compared to when a groove having the same depth as the cavity is provided.

[0081] 1 and 2 , in the sensor element described in paragraph 1, when the substrate 10 is placed on the package substrate 50, the substrate 10 has a first main surface F1 on which the insulating layer 20 is formed and a second main surface F2 that abuts against the package substrate 50, and the width of the groove G when the substrate 10 is viewed from the second main surface F2 side is shorter than one side of the cavity C. For example, the width of the groove G is 5% of one side of the cavity.

[0082] (Item 9) The sensor element according to item 1 further includes an electrode layer (wiring 30) formed on the membrane portion 2, as shown in FIGS.

[0083] By adopting such a configuration, a gas sensor can be realized, and the influence of fluctuations in atmospheric pressure on the detection results can be reduced.

[0084] (Clause 10) In another aspect, the present disclosure provides a semiconductor wafer 200 having a plurality of sensor elements as described in clause 1 arranged in a matrix, and as shown in Figures 14, 25 and 27, grooves provided in each sensor element are provided in a direction intersecting the cleavage plane BL of the substrate.

[0085] By adopting such a configuration, it is possible to reduce the possibility of unintended cracking in the wafer state.

[0086] (Item 11) In the semiconductor wafer 200 described in item 10, the substrate 10 is silicon, and the cleavage plane BL is a (111) plane or a (110) plane.

[0087] By adopting such a configuration, it is possible to reduce the possibility of unintended cracking in the wafer state.

[0088] (Clause 12) In another aspect, the present disclosure provides a semiconductor wafer 200 having a plurality of sensor elements as described in clause 1 arranged in a matrix, and as shown in Figures 25 and 27, in one column or one row of the plurality of sensor elements arranged in a matrix, a first sensor element 101 is arranged so that the groove direction is different from that of a second sensor element 101A or 101B.

[0089] By adopting such a configuration, it is possible to reduce the possibility of unintended cracking in the wafer state.

[0090] (Clause 13) In another aspect, the present disclosure provides a semiconductor wafer 200 having a plurality of sensor elements as described in clause 1 arranged in a matrix, and as shown in Figure 27, a dummy element 100D having no groove formed therein is arranged in one column or one row of the plurality of sensor elements arranged in a matrix.

[0091] By adopting such a configuration, it is possible to reduce the possibility of unintended cracking in the wafer state.

[0092] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0093] 2 membrane portion, 4, 6 peripheral portion, 10 substrate, 20 insulating layer, 21 first layer, 22 second layer, 23 third layer, 24 fourth layer, 30 wiring, 30a heater portion, 30b end portion, 30c connection portion, 30d pad portion, 31 barrier layer, 31a first portion, 31b second portion, 50 package substrate, 51 bonding material, 100, 101, 101A, 101B, 101C, 102, 103, 104, 105, 106 sensor element, 100D dummy element, 200 semiconductor wafer, C cavity, F1 first main surface, F2 second main surface, G, G2, G3, G4, G5, G6A, G6B, G8, G9 groove, G7C, G7B auxiliary groove, G7 communication path, G7A Main groove, H through hole.

Claims

1. A sensor element comprising: a substrate; and an insulating layer disposed on the substrate, wherein a cavity penetrating the substrate in the thickness direction is formed in the substrate; the insulating layer has a peripheral portion disposed on the substrate around the cavity and a membrane portion disposed on the cavity; and a groove extending from the cavity to the outer periphery of the substrate is formed in a part of the substrate located in the peripheral portion.

2. The sensor element according to claim 1, wherein when the substrate is placed on a package substrate, the groove forms one or more communication paths that connect the cavity with the outer periphery of the substrate.

3. A sensor element as described in claim 2, wherein when the substrate is viewed from the first main surface side on the membrane portion side to the second main surface side that abuts the package substrate, the communication path has a curved portion or a bent portion.

4. A sensor element as described in claim 2, wherein the substrate has a first main surface on the membrane portion side and a second main surface that abuts against the package substrate, and the substrate and the insulating layer have through holes formed therein that penetrate from the first main surface side toward the second main surface and communicate with the groove.

5. A sensor element according to claim 2, wherein the plurality of communication paths are formed by a main groove and an auxiliary groove spaced apart from the main groove and shallower than the main groove in the thickness direction of the substrate.

6. The sensor element according to claim 1, wherein the groove has a stepped shape with one or more steps in the thickness direction.

7. A sensor element as described in claim 1, wherein when the substrate is placed on a package substrate, the substrate has a first main surface on which the insulating layer is formed and a second main surface that abuts against the package substrate, and the depth of the groove from the second main surface in the thickness direction is shallower than the depth of the cavity.

8. A sensor element as described in claim 1, wherein when the substrate is placed on a package substrate, the substrate has a first main surface on which the insulating layer is formed and a second main surface that abuts against the package substrate, and the width of the groove when the substrate is viewed from the second main surface side is shorter than one side of the cavity.

9. The sensor element according to claim 1, further comprising an electrode layer formed on the membrane portion.

10. A semiconductor wafer having a plurality of sensor elements according to claim 1 arranged in a matrix, wherein the grooves provided in each sensor element are provided in a direction intersecting the cleavage plane of the substrate.

11. The semiconductor wafer according to claim 10, wherein the substrate is silicon and the cleavage plane is a (111) plane or a (110) plane.

12. A semiconductor wafer having a plurality of sensor elements according to claim 1 arranged in a matrix, wherein in one column or one row of the plurality of sensor elements arranged in the matrix, a first sensor element is arranged such that the groove direction differs from that of a second sensor element.

13. A semiconductor wafer having a plurality of sensor elements according to claim 1 arranged in a matrix, wherein a dummy element having no groove formed therein is arranged in one column or one row of the plurality of sensor elements arranged in the matrix.

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