JP2018006577A - Manufacturing method for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a semiconductor device that hinders a change in a separation distance between two substrates and also hinders failure in electrical and mechanical connection.SOLUTION: A manufacturing method for a semiconductor device comprises: preparing a cap substrate (10) on a first surface (10a) of which a first metal terminal (11) of annular shape is formed, and a semiconductor substrate (50) on a second surface (50a) of which a second metal terminal (51) of annular shape is formed; arranging the cap substrate and the semiconductor substrate opposite each other such that the first surface and the second surface are opposite; and approaching the cap substrate and the semiconductor substrate toward each other while heating the cap substrate and the semiconductor substrate, thereby metal-joining the first metal terminal and the second metal terminal. A double annular spacer (56) of constant height is formed in at least one of the first surface and the second surface. The cap substrate and the semiconductor substrate are approached toward each other such that a separation distance between the cap substrate and the semiconductor substrate is equal to the height of the spacer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a semiconductor device in which a cap substrate and a semiconductor substrate are metal-bonded.

  As shown in Patent Document 1, a bonded semiconductor bonded body in which a first semiconductor layer and a second semiconductor layer are bonded via a bonding metal layer is known. The bonding metal layer is bonded by bonding the first bonding metal layer formed on the bonding surface of the first semiconductor layer and the second bonding metal layer formed on the bonding surface of the second semiconductor layer to each other. Can be obtained.

JP-A-2005-44887

  As described above, in the bonded semiconductor bonded body disclosed in Patent Document 1, the first bonded metal layer and the second bonded metal layer are bonded to each other so that the first and second semiconductor layers are bonded together. To obtain a bonded metal layer. In this way, in order to bond the first bonding metal layer and the second bonding metal layer in close contact with each other, the first bonding metal layer and the second bonding metal layer are superposed and brought to a high temperature state. At this time, each of the first bonding metal layer and the second bonding metal layer is deformed in a lateral direction perpendicular to the overlapping direction due to the high temperature state and the pressure due to the overlapping. As a result, the distance between the first semiconductor layer and the second semiconductor layer may vary.

  Further, the bonded metal layer deformed in the lateral direction is electrically connected to an unintended region of the semiconductor layer, which may cause an electrical connection failure. Furthermore, as described above, each of the first bonding metal layer and the second bonding metal layer is deformed in a lateral direction different from the direction toward the first semiconductor layer and the second semiconductor layer to be bonded. Therefore, there is a possibility that the contact between each of the first bonded metal layer and the second bonded metal layer deformed in the lateral direction and the two semiconductor layers is uncertain. As a result, there is a risk of mechanical connection failure between the two semiconductor layers (two substrates).

  In view of the above problems, an object of the present invention is to provide a method of manufacturing a semiconductor device in which fluctuations in the separation distance between two substrates are suppressed and occurrence of electrical and mechanical connection failures is suppressed.

One of the disclosed inventions for achieving the above-described object includes a cap substrate (10) in which an annular first metal terminal (11) is formed on the first surface (10a), and an annular second metal. Preparing a semiconductor substrate (50) having terminals (51) formed on the second surface (50a);
The cap substrate and the semiconductor substrate are arranged to face each other so that the first surface and the second surface face each other,
While the cap substrate and the semiconductor substrate are heated, the cap substrate and the semiconductor substrate are brought close to each other to bring the first metal terminal and the second metal terminal into contact with each other, and the first metal terminal and the second metal terminal are metal-bonded. A method for manufacturing a semiconductor device, comprising:
At least one of the first surface and the second surface has a constant height that surrounds the periphery of the first metal terminal and the second metal terminal from the inside and the outside when the first metal terminal and the second metal terminal are joined together. A double annular spacer (56) is formed;
The first metal terminal and the second metal terminal are metal-bonded by bringing the cap substrate and the semiconductor substrate close to each other so that the distance between the cap substrate and the semiconductor substrate becomes the height of the spacer.

  Thus, according to the present invention, the distance between the cap substrate (10) and the semiconductor substrate (50) is defined by the spacer (56). Therefore, unlike the configuration in which the spacer (56) is not provided on the semiconductor substrate (50), the cap substrate (10) and the semiconductor substrate (50) are separated by deformation at the time of metal bonding of the metal terminals (11, 51). The fluctuation of the distance is suppressed.

  Further, the spacer has a double ring shape, and its height is constant. As described above, in the present invention, the cap substrate and the semiconductor substrate are brought close to each other so that the distance between the cap substrate and the semiconductor substrate becomes the height of the spacer. Accordingly, the first metal terminal (11) and the second metal terminal (51) are provided in the closed space constituted by the first surface (10a), the second surface (50a), and the spacer (56). . Therefore, even if each of the metal terminals (11, 51) is deformed by the contact, each of the metal terminals (11, 51) is suppressed from being electrically connected to an unintended region of the substrate (10, 50). As a result, the occurrence of poor electrical connection is suppressed.

  Furthermore, the deformation of the metal terminals (11, 51) is in the lateral direction perpendicular to the direction in which the cap substrate (10) and the semiconductor substrate (50) approach each other. Thus, each of the metal terminals (11, 51) is deformed in a lateral direction different from the direction toward the cap substrate (10) and the semiconductor substrate (50) to be joined. Therefore, there is a possibility that the contact between each of the laterally deformed metal terminals (11, 51) and the substrate (10, 50) becomes uncertain. However, as described above, the metal terminals (11, 51) are provided in a closed space constituted by the first surface (10a), the second surface (50a), and the spacer (56). Accordingly, when each of the laterally deformed metal terminals (11, 51) is in contact with the spacer (56), the laterally deformed metal terminals (11, 51) are transferred to the cap substrate (10) and the semiconductor substrate (50). Deforms in the direction it heads. For this reason, it becomes possible to prevent uncertain contact between the deformed metal terminals (11, 51) and the substrate (10, 50). As a result, the occurrence of mechanical connection failure between the cap substrate (10) and the semiconductor substrate (50) is suppressed.

  In addition, the code | symbol with the parenthesis is attached | subjected to the element as described in the claim as described in a claim, and each means for solving a subject. The reference numerals in parentheses are for simply indicating the correspondence with each component described in the embodiment, and do not necessarily indicate the element itself described in the embodiment. The description of the reference numerals with parentheses does not unnecessarily narrow the scope of the claims.

It is sectional drawing which shows the state by which the cap board | substrate and the semiconductor substrate were opposingly arranged. It is sectional drawing which shows schematic structure of an acceleration sensor. It is a top view for demonstrating the planar shape of a 1st metal terminal. It is a top view for demonstrating each planar shape of a 2nd metal terminal and a spacer. It is an expanded sectional view of the area | region A of FIG. It is an expanded sectional view of the area | region B of FIG. It is sectional drawing for demonstrating the 1st metal terminal of 2nd Embodiment. It is sectional drawing for demonstrating the metal terminal when a cap board | substrate and a semiconductor substrate are metal-joined. It is sectional drawing for demonstrating the 1st metal terminal of 3rd Embodiment. It is sectional drawing for demonstrating the metal terminal when a cap board | substrate and a semiconductor substrate are metal-joined. It is sectional drawing for demonstrating the 1st metal terminal of 4th Embodiment. It is sectional drawing for demonstrating the metal terminal when a cap board | substrate and a semiconductor substrate are metal-joined. It is sectional drawing for demonstrating the 1st metal terminal of 5th Embodiment. It is sectional drawing for demonstrating the metal terminal when a cap board | substrate and a semiconductor substrate are metal-joined. It is sectional drawing which shows the modification of an acceleration sensor.

Hereinafter, an embodiment in which the present invention is applied to an acceleration sensor manufacturing method will be described with reference to the drawings.
(First embodiment)
The acceleration sensor according to the present embodiment will be described with reference to FIGS. In FIG. 3, a through electrode 15 described later is omitted. In FIG. 4, a MEMS 55 and the like which will be described later are omitted. In order to clarify the configuration, the first metal terminal 11 is hatched in FIG. In FIG. 4, the second metal terminal 51 and the spacer 56 are hatched. Further, in FIG. 5 and FIG. 6, a through electrode 15 described later is omitted. In FIG. 6, the outer shape of the metal terminals 11, 51 is indicated by a broken line in order to show the originally formed positions of the metal terminals 11, 51.

  Hereinafter, the three directions orthogonal to each other are referred to as an x direction, a y direction, and a z direction. In the present embodiment, a plane defined by the x direction and the y direction is indicated as an xy plane.

  As shown in FIG. 2, the acceleration sensor 100 is formed by bonding a cap substrate 10 and a semiconductor substrate 50 via a metal connector 90. The metal connector 90 is formed by diffusion bonding the first metal terminal 11 of the cap substrate 10 and the second metal terminal 51 of the semiconductor substrate 50. Hereinafter, the cap substrate 10 and the semiconductor substrate 50 before metal bonding will be described individually.

  The cap substrate 10 of the present embodiment is made of a silicon substrate. As shown in FIG. 1, the cap substrate 10 is formed with a plurality of through holes 12 that penetrate the first surface 10 a facing the xy plane and the back surface 10 b on the back side in the z direction. Each of the wall surface constituting the through hole 12 and the back surface 10 b is covered with an insulating film 13. This insulating film 13 is made of silicon oxide or silicon nitride. A conductive film 14 is formed on the insulating film 13 on the wall surface constituting the through hole 12. The opening on the first surface 10 a side of the through hole 12 is closed by the conductive film 14. The conductive film 14 is made of, for example, aluminum. A through electrode 15 is formed by the conductive film 14 provided on the insulating film 13 covering the wall surface constituting the through hole 12 and the conductive film 14 provided in the opening on the first surface 10 a side of the through hole 12. Yes.

  A plurality of first metal terminals 11 that are electrically connected to the through electrodes 15 are formed on the first surface 10a. Some of the plurality of first metal terminals 11 are electrically connected to input / output terminals of the MEMS 55 described later via corresponding through electrodes 15. The remaining first metal terminals 11 are connected to the ground via the through electrodes 15 facing each other, and serve to perform metal bonding between the cap substrate 10 and the semiconductor substrate 50. FIG. 3 shows the remaining first metal terminals 11. The first metal terminal 11 has an annular shape in the xy plane. The height in the z direction is constant over the entire circumference. The first metal terminal 11 is made of aluminum.

  Note that the length (thickness) in the z direction of a part of the cap substrate 10 on the first surface 10a side is locally shortened. A locally recessed portion (hereinafter referred to as a recess 16) of the cap substrate 10 fulfills a function of enclosing a MEMS 55 described later. An annular first metal terminal 11 is provided on the first surface 10 a so as to surround the plurality of recesses 16.

  The semiconductor substrate 50 is an SOI substrate in which two semiconductor layers 53 and 54 are laminated via an insulating layer 52. The first semiconductor layer 53 has a second surface 50a facing the xy plane. As shown in FIG. 1, the semiconductor layers 53 and 54 and the insulating layer 52 are finely processed by a well-known etching technique. By this fine processing, MEMS 55 (Micro Electro Mechanical Systems) is formed on the surface layer on the second surface 50a side.

  The MEMS 55 includes a floating portion made of the first semiconductor layer 53 floating with respect to the second semiconductor layer 54 without the insulating layer 52, and a first semiconductor layer fixed to the second semiconductor layer 54 with the insulating layer 52 interposed therebetween. 53, and a fixing portion. The floating portion includes a weight portion forming the center of mass, a movable electrode formed on the weight portion, and a spring-like beam portion connected to the weight portion. The fixed portion includes an anchor for connecting and fixing the beam portion, and a fixed electrode disposed to face the movable electrode in the xy plane. A capacitor is constituted by the movable electrode and the fixed electrode. The fixed electrode may be stationary with respect to the second semiconductor layer 54, and may not be fixed to the second semiconductor layer 54 via the insulating layer 52. That is, the fixed electrode may be included in the floating portion.

  When acceleration is applied to the acceleration sensor 100, an inertial force is generated in the weight portion. As a result, the beam portion expands and contracts, and the weight portion is displaced. As a result, the facing interval and facing area between the movable electrode and the fixed electrode vary, and the capacitance of the capacitor changes. In this way, the capacitance of the capacitor changes due to the application of acceleration. Therefore, acceleration can be detected based on the change in capacitance. A detection signal indicating the change in capacitance is output to a wiring pattern (not shown) formed on the second surface 50 a of the semiconductor substrate 50.

  In addition to the above wiring pattern, a plurality of second metal terminals 51 are formed on the second surface 50a. A part of the plurality of second metal terminals 51 is electrically connected to the wiring pattern. The remaining second metal terminals 51 are connected to the ground and serve to metal-bond the cap substrate 10 and the semiconductor substrate 50. FIG. 4 shows the remaining second metal terminal 51. The second metal terminal 51 has an annular shape in the xy plane. The height in the z direction is constant over the entire circumference. The second metal terminal 51 is made of aluminum.

  In addition to the wiring pattern and the second metal terminal 51, a double annular spacer 56 surrounding the periphery of the annular second metal terminal 51 from the inside and the outside is also formed on the second surface 50a. The spacer 56 is made of silicon oxide, silicon nitride, or polysilicon. The spacer 56 has an annular inner spacer provided inside the second metal terminal 51 in the xy plane, and an annular outer spacer provided outside the second metal terminal 51. The number of these inner spacers and outer spacers is not limited to one.

  The height of the spacer 56 in the z direction is constant, and the annular upper end surface 56a farthest from the second surface 50a faces the xy plane. As shown in FIG. 5, the height in the z direction of the spacer 56 is h1, which is longer than the heights h2 and h3 in the z direction of the second metal terminal 51 and the first metal terminal 11, respectively. However, the height h1 of the spacer 56 is shorter than the height h2 + h3 obtained by adding the heights h2 and h3 of the second metal terminal 51 and the first metal terminal 11 respectively.

  The lateral width of the xy plane of the spacer 56 is w1. That is, the distance between the inner spacer and the outer spacer in the xy plane is w1. The lateral width w1 of the spacer 56 is longer than the longest lateral widths w2 and w3 of the xy planes of the second metal terminal 51 and the first metal terminal 11, respectively. Furthermore, the volume of the area surrounding the first metal terminal 11 and the second metal terminal 51 in the spacer 56 from the inside and the outside is the sum of the corresponding volumes of the second metal terminal 51 and the first metal terminal 11. It is larger than the combined volume. That is, the volume of the region between the inner spacer and the outer spacer is larger than the above combined volume. In the present embodiment, the lateral width w2 is longer than the lateral width w3. However, on the contrary, a configuration in which the lateral width w3 is longer than the lateral width w2 can be adopted.

  Next, metal bonding between the cap substrate 10 and the semiconductor substrate 50 will be described in detail. The z direction shown below is along the vertical direction.

  A plurality of cap substrates 10 are included in the first wafer. Similarly, a plurality of semiconductor substrates 50 are included in the second wafer. First, the first wafer and the second wafer are prepared. Then, the first wafer is fixed on the first heat table. At this time, the back surface 10b is brought into contact with the mounting surface of the first heat table. Similarly, the second wafer is mounted on the second heat table and fixed. At this time, the back surface of the second surface 50a is brought into contact with the mounting surface of the second heat table.

  Next, as shown in FIG. 1, the cap substrate 10 and the semiconductor substrate 50 are arranged to face each other so that the first surface 10 a and the second surface 50 a face each other in the z direction. At this time, the recess 16 and the MEMS 55 are opposed to each other, and the first metal terminal 11 and the second metal terminal 51 are opposed to each other. Then, each of the cap substrate 10 and the semiconductor substrate 50 is heated by a heat table. Thereby, each of the first metal terminal 11 and the second metal terminal 51 is brought into a high temperature state. Note that before the cap substrate 10 and the semiconductor substrate 50 are disposed to face each other, the first wafer and the second wafer may be heated by the heat table.

  Next, as shown by the white arrow in FIG. 1, the cap substrate 10 and the semiconductor substrate 50 are brought close to each other in the z direction. Thereby, the 1st metal terminal 11 and the 2nd metal terminal 51 are made to contact. When the first metal terminal 11 and the second metal terminal 51 come into contact with each other, diffusion bonding is started at the interface. In FIG. 1, the cap substrate 10 on which the through electrode 15 is formed and the semiconductor substrate 50 are illustrated as being metal-bonded. However, the cap substrate 10 on which the through electrode 15 is not formed and the semiconductor substrate 50 are made of metal. You may join. In the case of this modification, the through electrode 15 is formed on the cap substrate 10 after the cap substrate 10 and the semiconductor substrate 50 are metal-bonded.

  The cap substrate 10 and the semiconductor substrate 50 are brought close to each other until the entire upper end surface 56a of the spacer 56 contacts the first surface 10a. As described above, the height h1 of the spacer 56 in the z direction is shorter than h2 + h3 obtained by adding the heights h2 and h3 of the second metal terminal 51 and the first metal terminal 11, respectively. Therefore, each of the first metal terminal 11 and the second metal terminal 51 is deformed in a direction along the xy plane (hereinafter, referred to as a lateral direction) by the pressure due to the approach between the cap substrate 10 and the semiconductor substrate 50. However, as described above, the volume of the region surrounded by the spacer 56 is larger than the total volume obtained by adding the volumes of the first metal terminal 11 and the second metal terminal 51. Therefore, as shown in FIG. 6, the first metal terminal 11 and the second metal terminal 51 are all prevented from leaking out from the sealed space formed by the first surface 10 a, the second surface 50 a, and the spacer 56. .

  The first metal terminal 11 and the second metal terminal 51 deformed in the lateral direction may come into contact with the inner ring surface 56 b of the spacer 56. When contact is made in this way, the deformation directions of the first metal terminal 11 and the second metal terminal 51 change from the lateral direction to the z direction. The first metal terminal 11 and the second metal terminal 51 changed in the z direction come into contact with the first surface 10a and the second surface 50a.

  Next, the effect of the manufacturing method of the acceleration sensor 100 according to the present embodiment will be described. As described above, the cap substrate 10 and the semiconductor substrate 50 are brought close to each other until the entire upper end surface 56a of the spacer 56 contacts the first surface 10a. According to this, the distance between the cap substrate 10 and the semiconductor substrate 50 is defined by the height h 1 of the spacer 56. Therefore, unlike the configuration in which the spacer 56 is not provided on the semiconductor substrate 50, the separation distance between the cap substrate 10 and the semiconductor substrate 50 varies due to deformation of the first metal terminal 11 and the second metal terminal 51 at the time of metal bonding. It is suppressed.

  Further, at the time of metal bonding, the first metal terminal 11 and the second metal terminal 51 are each brought into a high temperature state, but the metal terminals 11 and 51 in the high temperature state are easily deformed. Therefore, there is a possibility that the metal terminals 11 and 51 are deformed at the time of metal bonding, and the metal terminals 11 and 51 are electrically connected to unintended portions of the substrates 10 and 50, respectively. However, as described above, the second metal terminal 51 is surrounded by the double annular spacer 56. The entire upper end surface 56a of the spacer 56 comes into contact with the first surface 10a, thereby closing the opening. Further, the volume of the region surrounded by the spacer 56 is larger than the total volume obtained by adding the volumes of the metal terminals 11 and 51. Therefore, it is possible to prevent the deformed metal terminals 11 and 51 from leaking out from the sealed space formed by the first surface 10 a, the second surface 50 a, and the spacer 56. Accordingly, it is possible to prevent the deformed metal terminals 11 and 51 from being electrically connected to unintended regions of the substrates 10 and 50, respectively. As a result, the occurrence of poor electrical connection is suppressed.

  Furthermore, the deformation of the metal terminals 11 and 51 is a lateral direction orthogonal to the z direction in which the substrates 10 and 50 approach each other. Thus, each of the metal terminals 11 and 51 is deformed in a lateral direction different from the z direction toward the substrates 10 and 50 to be joined. Therefore, there is a possibility that the contact between the metal terminals 11 and 51 deformed in the lateral direction and the substrates 10 and 50 becomes uncertain. However, as described above, the second metal terminal 51 is surrounded by the double annular spacer 56. Therefore, when the deformed metal terminals 11 and 51 are in contact with the spacer 56, the deformed metal terminals 11 and 51 are deformed in the z direction toward the substrates 10 and 50. For this reason, it is suppressed that the contact between the deformed metal terminals 11 and 51 and the substrates 10 and 50 becomes uncertain. As a result, the mechanical connection failure between the cap substrate 10 and the semiconductor substrate 50 is suppressed.

  The surface of all substances has surface irregularities although they are fine. Therefore, fine surface irregularities also exist on the upper end surface 56 a of the spacer 56. Further, fine surface irregularities also exist on the first surface 10 a of the cap substrate 10. Therefore, the space constituted by the first surface 10a, the second surface 50a, and the spacer 56 does not constitute a strictly closed space. However, the space formed by the first surface 10a, the second surface 50a, and the spacer 56 is blocked to the extent that the metal terminals 11 and 51 deformed as described above do not leak outside. Therefore, this space is described as a closed space.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS.

  In addition, the acceleration sensor according to each embodiment described below has much in common with the above-described embodiment. Therefore, in the following description, description of common parts is omitted, and different parts are mainly described. In the following description, the same reference numerals are given to the same elements as those described in the above embodiment.

  In the first embodiment, as shown in FIG. 3, the first metal terminal 11 has an example in which the height in the z direction is uniform at h3. On the other hand, in this embodiment, as shown in FIG. 7, it is also possible to adopt a configuration in which a part of the first metal terminal 11 protrudes partially. The protrusion has an annular shape along the direction in which the first metal terminal 11 extends in an annular shape. However, this protrusion does not need to form an annular shape, and its planar shape is not particularly limited.

  According to this, when the cap substrate 10 and the semiconductor substrate 50 are brought close to each other and the first metal terminal 11 and the second metal terminal 51 are metal-bonded, the first metal as shown by a broken line in FIG. Part of the second metal terminal 51 can be punched by the tip of the part of the terminal 11 that protrudes partially. As a result, the metal terminals 11 and 51 are deformed to expose the new surfaces, and the new surfaces contact each other. Further, the contact area between the first metal terminal 11 and the second metal terminal 51 is increased. For this reason, the first metal terminal 11 and the second metal terminal 51 can be metal-bonded without increasing the heating temperature at the time of metal bonding of the first metal terminal 11 and the second metal terminal 51 so much.

  Note that the acceleration sensor 100 according to the present embodiment includes components equivalent to the acceleration sensor 100 described in the first embodiment. Therefore, it cannot be overemphasized that there exists an equivalent effect.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS.

  In the first embodiment, as shown in FIG. 3, the first metal terminal 11 has an example in which the height in the z direction is uniform at h3. On the other hand, the present embodiment is characterized in that the first metal terminal 11 corresponding to one second metal terminal 51 is divided into a plurality of rings so as to form an annular shape as shown in FIG.

  According to this, in the same manner as the acceleration sensor 100 described in the second embodiment, when the first metal terminal 11 and the second metal terminal 51 are metal-joined, a plurality of them are shown in a pseudo manner with broken lines in FIG. A part of the second metal terminal 51 can be drilled by the tip of the first metal terminal 11 divided into two. As a result, the metal terminals 11 and 51 are deformed to expose the new surfaces, and the new surfaces contact each other. Further, the contact area between the first metal terminal 11 and the second metal terminal 51 is increased. For this reason, the first metal terminal 11 and the second metal terminal 51 can be metal-bonded without increasing the heating temperature at the time of metal bonding of the first metal terminal 11 and the second metal terminal 51 so much.

  Note that the acceleration sensor 100 according to the present embodiment includes components equivalent to the acceleration sensor 100 described in the first embodiment. Therefore, it cannot be overemphasized that there exists an equivalent effect.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIGS.

  In the first embodiment, an example in which only the first metal terminal 11 is formed on the first surface 10a as an element for joining the substrates 10 and 50 has been described. On the other hand, this embodiment is characterized in that a plurality of protrusions 60 made of a material harder than each of the metal terminals 11 and 51 are formed in addition to the first metal terminal 11 as shown in FIG. The protrusion 60 has an annular shape along the direction in which the first metal terminal 11 extends in an annular shape. However, the protrusion 60 does not have to be annular, and the planar shape is not particularly limited.

  The protrusion 60 is made of at least one of polysilicon, silicon oxide, and silicon nitride. A plurality of protrusions 60 are formed on the first surface 10 a for one first metal terminal 11. The plurality of protrusions 60 are covered with the first metal terminal 11. The height in the z direction of the first metal terminal 11 provided on the end surface 60a of the protrusion 60 is partially increased. Thereby, the first metal terminal 11 protrudes partially. The height of the protrusion 60 in the z direction is h4. The longest height in the z direction from the first surface 10a of the first metal terminal 11 protruding due to the protruding portion 60 is h3. The longest lateral width of the projection 60 in the xy plane is w4, which is narrower than the longest lateral width w3 of the first metal terminal 11.

  According to this, in the same manner as the acceleration sensor 100 described in the second embodiment, when the first metal terminal 11 and the second metal terminal 51 are metal-joined, a plurality of them are shown in a pseudo manner with broken lines in FIG. A part of the second metal terminal 51 can be drilled by the tip of the first metal terminal 11. However, the protrusion of the first metal terminal 11 is supported by a protrusion 60 that is harder than the metal terminals 11 and 51. Therefore, compared to a configuration in which the protrusion is formed only by the first metal terminal 11, the other part of the second metal terminal 51 is easily pierced by the protrusion of the first metal terminal 11. Therefore, each of the metal terminals 11 and 51 is deformed to easily expose the new surface, and the new surfaces are easily brought into contact with each other. Further, the contact area between the first metal terminal 11 and the second metal terminal 51 is likely to increase. As a result, the first metal terminal 11 and the second metal terminal 51 can be metal-bonded without significantly increasing the temperature at which the first metal terminal 11 and the second metal terminal 51 are heated at the time of metal bonding.

  Further, the volume of the region surrounding the first metal terminal 11 and the second metal terminal 51 from the inner side and the outer side in the spacer 56 of the present embodiment is not only the metal terminals 11 and 51 but also the volumes of the projections 60. It is larger than the combined volume. Therefore, it is possible to prevent the deformed metal terminals 11 and 51 from leaking out from the sealed space formed by the first surface 10 a, the second surface 50 a, and the spacer 56. Accordingly, it is possible to prevent the deformed metal terminals 11 and 51 from being electrically connected to unintended regions of the substrates 10 and 50, respectively. As a result, the occurrence of poor electrical connection is suppressed.

  Note that the acceleration sensor 100 according to the present embodiment includes components equivalent to the acceleration sensor 100 described in the first embodiment. Therefore, it cannot be overemphasized that there exists an equivalent effect.

  Furthermore, in the present embodiment, the number of the protrusions 60 may be singular.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIGS.

  In 4th Embodiment, as shown in FIG. 11, the some protrusion part 60 showed the example covered with the one 1st metal terminal 11. As shown in FIG. On the other hand, the present embodiment is characterized in that each of the plurality of protrusions 60 is independently covered with a corresponding divided annular first metal terminal 11 as shown in FIG.

  According to this, in the same manner as the acceleration sensor 100 described in the fourth embodiment, when the first metal terminal 11 and the second metal terminal 51 are metal-joined, as shown in a pseudo manner with broken lines in FIG. A part of the second metal terminal 51 can be punched by the tips of the plurality of first metal terminals 11 formed. Thereby, each of the metal terminals 11 and 51 can be deformed to expose the new surfaces, and the new surfaces can be brought into contact with each other. Further, the contact area between the first metal terminal 11 and the second metal terminal 51 can be increased.

  Note that the acceleration sensor 100 according to the present embodiment includes components equivalent to the acceleration sensor 100 described in the first embodiment. Therefore, it cannot be overemphasized that there exists an equivalent effect.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

(First modification)
In each embodiment, the example in which the spacer 56 is formed on the second surface 50a is shown. However, differently, a configuration in which the spacer 56 is formed on the first surface 10a may be employed. In this case, at the time of metal bonding, the cap substrate 10 and the semiconductor substrate 50 are brought closer to each other in the z direction so that the upper end surface 56a of the spacer 56 formed on the first surface 10a is in contact with the second surface 50a over the entire circumference.

  A configuration in which spacers 56 are formed on each of the first surface 10a and the second surface 50a may be employed. In this case, at the time of metal bonding, the cap substrate 10 and the semiconductor are arranged such that the upper end surface 56a of the spacer 56 formed on the first surface 10a and the upper end surface 56a of the spacer 56 formed on the second surface 50a are in contact with each other over the entire circumference. The substrate 50 is brought close to each other in the z direction.

(Second modification)
In each embodiment, the example in which only the double annular spacer 56 is formed on the second surface 50a is shown. However, unlike this, for example, the configuration shown in FIG. 15 may be employed. That is, the cylindrical spacer 57 surrounding the first metal terminal 11 electrically connected to the input / output terminal of the MEMS 55 and the second metal terminal 51 electrically connected to the wiring pattern of the second surface 50a is the first. A configuration formed on at least one of the surface 10a and the second surface 50b can also be adopted. The height of the spacer 57 in the z direction is the same as the height of the spacer 56 in the z direction.

(Third Modification)
In 2nd Embodiment-5th Embodiment, the example in which the 1st metal terminal 11 protruded was shown. However, unlike this, a configuration in which the second metal terminal 51 protrudes may be employed. Moreover, the structure which each metal terminal 11 and 51 protruded is also employable. However, in this case, one of the protrusions of the metal terminals 11 and 51 is narrower in width than the other protrusion. When the metal terminals 11 and 51 are brought into contact with each other, a plurality of one protrusions are brought into contact with one of the other protrusions.

(Fourth modification)
In 4th Embodiment and 5th Embodiment, the example in which the projection part 60 was formed in the 1st surface 10a was shown. However, it is also possible to adopt a configuration in which the protrusion 60 is formed on the second surface 50a.

(Fifth modification)
In each embodiment, an example in which the first metal terminal 11 and the second metal terminal 51 are diffusion-bonded by heating the cap substrate 10 and the semiconductor substrate 50 with a heat table and bringing them closer to each other in the z direction has been described. However, at this time, at least one of the cap substrate 10 and the semiconductor substrate 50 may be finely vibrated by applying ultrasonic waves to the heat table. According to this, when the 1st metal terminal 11 and the 2nd metal terminal 51 contact, the metal oxide formed in each surface of the 1st metal terminal 11 and the 2nd metal terminal 51 by micro vibration becomes easy to be removed. Thereby, the new surfaces in the metal terminals 11 and 51 are easily brought into contact with each other, and the first metal terminal 1 and the second metal terminal 51 are easily diffusion-bonded.

(Sixth Modification)
In each embodiment, the example which each metal terminal 11 and 51 consists of aluminum was shown. However, the forming material of each of the metal terminals 11 and 51 is not limited to the above example, and is made of at least one of aluminum, gold, silver, copper, zinc, tin, germanium, gallium, and oxides thereof. That's fine. That is, the forming material of each of the metal terminals 11 and 51 may be a single metal material, an alloy composed of a plurality of metal materials, and an oxidized metal material. The metal terminals 11 and 51 may be formed of different materials.

  More specifically, at least one of the metal terminals 11 and 51 may be configured by laminating a plurality of types of metal layers having different hardnesses. For example, the 1st metal terminal 11 can employ | adopt the structure by which the 1st metal and the 2nd metal were laminated | stacked in order from the 1st surface 10a. Here, the second metal constitutes the tip of the first metal terminal 11 and is made of a material harder than the first metal. In the case of such a configuration, the second metal terminal 51 is pierced by the tip of the first metal terminal 11 when the first metal terminal 11 comes into contact with the second metal terminal 51 as compared with the configuration in which the first metal terminal 11 is simply made of the first metal. It becomes easy. And it becomes easy to remove the metal oxide formed on the surface of the second metal terminal 51.

(Other variations)
In each embodiment, the example which applied the semiconductor device described in this invention to the acceleration sensor was shown. However, the semiconductor device is not limited to the above example, and for example, an angular velocity sensor or an electronic circuit can be employed.

  In each embodiment, an example in which the cap substrate 10 is a silicon substrate has been described. However, the material for forming the cap substrate 10 is not limited to the above example, and for example, a glass substrate or a metal substrate may be employed.

DESCRIPTION OF SYMBOLS 10 ... Cap board | substrate 10a ... 1st surface 11 ... 1st metal terminal 50 ... Semiconductor substrate 50a ... 2nd surface 56 ... Spacer 100 ... Acceleration sensor

Claims (10)

A cap substrate (10) having an annular first metal terminal (11) formed on the first surface (10a), and a semiconductor substrate having an annular second metal terminal (51) formed on the second surface (50a). Prepare (50)
The cap substrate and the semiconductor substrate are arranged to face each other so that the first surface and the second surface face each other,
The first metal terminal and the second metal terminal are brought into contact with each other by bringing the cap substrate and the semiconductor substrate closer to each other while heating the cap substrate and the semiconductor substrate, respectively, and the first metal terminal and the first metal terminal A method of manufacturing a semiconductor device in which two metal terminals are metal-bonded,
At least one of the first surface and the second surface has a periphery around the first metal terminal and the second metal terminal from the inside and the outside during metal bonding of the first metal terminal and the second metal terminal. A double-circular spacer (56) having a constant surrounding height is formed;
A semiconductor that metal-joins the first metal terminal and the second metal terminal by bringing the cap substrate and the semiconductor substrate close to each other so that a distance between the cap substrate and the semiconductor substrate becomes the height of the spacer. Device manufacturing method. At least one of the first metal terminal and the second metal terminal partially protrudes;
By bringing the cap substrate and the semiconductor substrate close to each other, at least one of the first metal terminal and the second metal terminal has a protruding portion at a part thereof, so that the first metal terminal and the second metal terminal are The method of manufacturing a semiconductor device according to claim 1, wherein at least a part of the other is drilled and the first metal terminal and the second metal terminal are metal-bonded. At least one of the first metal terminal and the second metal terminal is divided so as to form a ring shape;
By bringing the cap substrate and the semiconductor substrate close to each other, at least one of the first metal terminal and the second metal terminal is overlapped with the tip of the portion that forms an annular shape, and the first metal terminal and the second metal terminal 2. The method of manufacturing a semiconductor device according to claim 1, wherein at least a part of the first metal terminal and the second metal terminal are metal-bonded.   The volume of the region surrounding each of the first metal terminal and the second metal terminal in the spacer from the inner side and the outer side is equal to or greater than the total volume obtained by adding the volumes of the second metal terminal and the first metal terminal. The manufacturing method of the semiconductor device of any one of Claims 1-3. On one of the first surface and the second surface, a protrusion (60) made of a forming material harder than each of the first metal terminal and the second metal terminal is formed,
A part of one of the first metal terminal and the second metal terminal is provided on the end surface (60a) of the protrusion to protrude.
By bringing the cap substrate and the semiconductor substrate close to each other, the first metal terminal and the first metal terminal and the second metal terminal are provided at the tip of one protruding portion of the first metal terminal and the second metal terminal. 4. The method of manufacturing a semiconductor device according to claim 2, wherein a part of the other of the second metal terminals is drilled and the first metal terminal and the second metal terminal are metal-bonded.   The volume of the area surrounding the first metal terminal and the second metal terminal in the spacer from the inside and the outside is the sum of the volumes of the first metal terminal, the second metal terminal, and the protrusion. The method for manufacturing a semiconductor device according to claim 5, wherein the total volume is equal to or greater than the total volume.   The method for manufacturing a semiconductor device according to claim 5, wherein a material for forming the protrusion is at least one of polysilicon, silicon oxide, and silicon nitride.   The forming material of each of the first metal terminal and the second metal terminal is at least one of aluminum, gold, silver, copper, zinc, tin, germanium, gallium, and oxides thereof. The manufacturing method of the semiconductor device of any one of -7. The cap substrate is formed with a through electrode (15) that electrically connects the first surface and the back surface (10b) on the back surface thereof,
On the surface layer on the second surface side of the semiconductor substrate, MEMS (55) is formed,
The first surface side of the through electrode and the first metal terminal are electrically connected, and the MEMS and the second metal terminal are electrically connected. Semiconductor device manufacturing method.   While the cap substrate and the semiconductor substrate are heated, at least one of the cap substrate and the semiconductor substrate is vibrated by ultrasonic waves, the spacer is in contact with the first surface, and the opening of the spacer is the first portion. By bringing the cap substrate and the semiconductor substrate close to each other so as to be blocked by a surface, the first metal terminal and the second metal terminal are brought into contact with each other, and the first metal terminal and the second metal terminal are brought into contact with each other. The method for manufacturing a semiconductor device according to claim 1, wherein metal bonding is performed.

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