JP4840771B2 - Method for manufacturing mechanical quantity sensor - Google Patents

Description

The present invention relates to a method for manufacturing a mechanical quantity sensor that detects various mechanical quantities such as acceleration and angular velocity.

  Conventionally, in a mechanical quantity sensor such as an acceleration sensor or an angular velocity sensor, in order to improve the detection sensitivity of the sensor unit (detection unit), various contrivances have been made to improve the degree of vacuum of a sealed chamber that houses the sensor unit. ing. In particular, the mechanical quantity sensor for detecting the angular velocity needs to excite the sensor portion in advance, but in order to increase the Q value and increase the measurement sensitivity, the vibration is not hindered by the viscosity of the air (damping). It is necessary to create a high vacuum in the sealed chamber. Therefore, the degree of vacuum in the sealed chamber is one of the important factors that determine quality and performance.

  In general, when a mechanical quantity sensor is manufactured, a glass substrate is bonded to both surfaces of a silicon substrate by anodic bonding so that the sensor unit is accommodated in a sealed chamber. For this reason, it is necessary to evacuate the sealed chamber before or after anodic bonding. Various devices have been devised for this technique. As one of them, the evacuation passage formed in the glass substrate in advance is used to perform evacuation after anodic bonding, and after the evacuation is completed, the evacuation passage is sealed by film formation and sealed. A method of vacuum-sealing a room is known (for example, see Patent Document 1).

FIG. 18 shows a cross-sectional view of a mechanical quantity sensor manufactured by this method. As shown in FIG. 18, the mechanical quantity sensor 40 includes a silicon substrate 41 and glass substrates 42 bonded to both surfaces of the silicon substrate 41. In addition, the sensor unit 45 is housed in a sealed state in a sealed chamber 44 surrounded by a through hole 43 formed in the silicon substrate 41 and both glass substrates 42. Further, an exhaust groove 46 communicating with the sealed chamber 44 is formed in the silicon substrate 41, and an exhaust hole 47 communicating with the exhaust groove 46 is formed in the glass substrate 42. The exhaust holes 47 and the exhaust grooves 46 are closed by a thin film 48 formed on the glass substrate 42. Thereby, the sealed chamber 44 is sealed.
The exhaust groove 46 and the exhaust hole 47 constitute a vacuum exhaust passage 49 when evacuating. Further, when the mechanical quantity sensor 40 is viewed from the side, the exhaust groove 46 cannot be confirmed from the outside.

  Next, a method of vacuum-sealing the inside of the sealed chamber 44 when manufacturing the mechanical quantity sensor 40 will be briefly described with reference to FIGS. FIG. 19 is a plan view seen from above the glass substrate 42 after the silicon substrate 41 in which the through holes 43, the sensor portions 45 and the exhaust grooves 46 are formed, and the glass substrate 42 in which the exhaust holes 47 are formed. is there. 20 is a cross-sectional view taken along line FF shown in FIG. FIG. 21 is a top view of FIG. 20 viewed from the glass substrate 42 side.

  First, an exhaust hole 47 is formed in the glass substrate 42 and an exhaust groove 46 is formed in the silicon substrate 41 to form a vacuum exhaust passage 49. Thereafter, as shown in FIG. 19, the silicon substrate 41 and the glass substrate 42 are overlapped so that each exhaust hole 47 and the exhaust groove 46 communicate with each other, and then joined by anodic bonding, and the sensor portion is placed in the sealed chamber 44. 45 is accommodated. At this time, the sealed chamber 44 is in communication with the outside via the vacuum exhaust passage 49. Then, after anodic bonding, the glass substrate 42 and the silicon substrate 41 bonded together are placed in a vacuum chamber (not shown) and evacuated. As a result, the sealed chamber 44 is evacuated through the exhaust groove 46 and the exhaust hole 47, so that the sealed chamber 44 is in a vacuum state. After the evacuation is completed, a thin film 48 is formed on the surface of the glass substrate 42 on which the exhaust holes 47 are formed by sputtering or vapor deposition, and the exhaust grooves 46 and the exhaust holes 47 are filled with the thin film 48. Thereby, the inside of the sealed chamber 44 can be vacuum-sealed.

According to this method, since the sealed chamber 44 can be immediately vacuum-sealed by film formation after evacuation, the degree of vacuum in the sealed chamber 44 can be improved. At present, in order to further improve the degree of vacuum of the sealed chamber 44, the shape of the exhaust groove 46 is changed to devise to reduce the flow path resistance.
JP-A-11-351876

However, the following problems remain in the conventional method.
That is, in general, when the mechanical quantity sensor 40 is manufactured, a large amount of the mechanical quantity sensor 40 is manufactured at a time using one large wafer as the silicon substrate 41. That is, after a plurality of sensor portions 45 are formed on the wafer by semiconductor technology, the glass substrate 42 is bonded to both surfaces of the wafer, and finally the wafer is diced into a lattice shape to produce a plurality of mechanical quantity sensors 40. is doing. Therefore, vacuuming is also performed in a state where a wafer having glass substrates 42 bonded on both sides is put in a vacuum chamber. At this time, the vacuum exhaust passages 49 are formed as many as the plurality of sealed chambers 44 in which the sensor units 45 are accommodated, and vacuuming is performed for each chip.

  However, since the wafer has been subjected to various processes such as etching until the evacuation is performed, the processing accuracy is inevitably varied. For this reason, the plurality of sealed chambers 44 and the vacuum exhaust passages 49 also have variations in processing accuracy. Therefore, even if the entire wafer is evacuated for the same time, the inside of the plurality of sealed chambers 44 does not have the same degree of vacuum, and inevitably varies. As a result, even if the plurality of vacuum exhaust passages 49 are sealed at the same timing by film formation, the degree of vacuum of the plurality of mechanical quantity sensors 40 manufactured from the same wafer cannot be stabilized at a certain level. It was difficult to stabilize the quality. That is, it has been difficult to stably manufacture a plurality of mechanical quantity sensors 40 of a certain quality by eliminating variations in the degree of vacuum between chips. Further, even if the shape of the exhaust groove 46 is changed, the above problem is for the entire wafer, so that the variation in the degree of vacuum cannot be reduced.

  The present invention has been made in view of such circumstances, and its object is to eliminate the variation in the degree of vacuum between chips as much as possible and to stably manufacture a mechanical sensor of uniform quality. It is an object to provide a manufacturing method of a quantity sensor, a mechanical quantity sensor manufactured by the manufacturing method of the mechanical quantity sensor, and an electronic device having the mechanical quantity sensor.

The present invention provides the following means in order to solve the above problems.
The method of manufacturing a mechanical quantity sensor of the present invention includes a sensor unit that detects a mechanical quantity acting from the outside using a semiconductor substrate, one glass substrate bonded to both surfaces of the semiconductor substrate, and the other glass substrate. A plurality of mechanical quantity sensors at a time, wherein a plurality of through holes surrounded by walls are formed in the semiconductor substrate, and the plurality of mechanical quantity sensors are disposed in the plurality of through holes. A sensor part forming step for forming each sensor part, an exhaust groove forming step for forming an exhaust groove connecting adjacent through holes with a predetermined depth on the surface of the semiconductor substrate, and a plurality of the wall parts A communication groove forming step of forming a communication groove communicating with the exhaust groove so as to surround the periphery of the through hole deeper than the exhaust groove; and when the one glass substrate is overlaid on the semiconductor substrate, the exhaust groove A little In addition, a first exhaust hole is formed in the glass substrate so as to communicate with the outside in the vicinity of the through hole, and a plurality of second exhaust holes are formed along the communication groove so as to communicate the communication groove with the outside. An exhaust hole forming step, and a joining step of joining the one glass substrate to one surface of the semiconductor substrate in which the exhaust groove is formed and joining the other glass substrate to the other surface of the semiconductor substrate. And after the joining step, a vacuum step of evacuating a sealed chamber surrounded by the through hole and the first and second glass substrates via the communication groove and the exhaust groove, and the vacuum step Thereafter, a sealing step of forming a thin film on the surface of the one glass substrate in vacuum and vacuum-sealing the sealed chamber, and the semiconductor substrate and the one integrally bonded after the sealing step Glass substrate and the second glass substrate And it is characterized in that it comprises a cutting step of Katahen into several cut along the communication groove.

  In the manufacturing method of the mechanical quantity sensor according to the present invention, by performing the sensor part forming process, the exhaust groove forming process, the communication groove forming process, the exhaust hole forming process, the joining process, the vacuum process, the sealing process, and the cutting process, A plurality of sealed mechanical quantity sensors in which sensor portions for detecting acceleration, angular velocity, and the like are sealed in a sealed chamber can be manufactured at a time. In addition, each process except a vacuum process, a sealing process, and a cutting process may be performed simultaneously, and a process order is not limited.

  First, a sensor part forming step is performed in which a through hole surrounded by a wall part is formed in a semiconductor substrate such as a silicon substrate, and a sensor part supported by a beam part or the like is formed in each of the plurality of through holes. Do. In addition, these several through-holes become a sealed chamber which seals a sensor part later. And the exhaust groove formation process which forms the exhaust groove which connects adjacent through-holes to the surface of a semiconductor substrate is performed. At this time, the exhaust groove is formed to have a predetermined depth. Thereby, even if the glass substrate is stacked on the side where the exhaust groove is formed, each through hole is in a state of communicating with the adjacent through hole through the exhaust groove.

  Next, a communication groove forming step is performed in which a communication groove is formed in the wall portion of the semiconductor substrate blocking between the through holes. At this time, a groove is formed deeper than the exhaust groove along the wall. As a result, the periphery of each through hole can be surrounded by the communication groove, and the exhaust groove that connects adjacent through holes is crossed and communicated with the exhaust groove. Therefore, when the glass substrate is stacked on the side where the exhaust groove is formed, each through hole not only communicates with the adjacent through hole via the exhaust groove, but also other through holes via the communication groove and the exhaust groove. It will be in the state connected with. That is, each through hole is in a state of being in communication with each other via the communication groove and the exhaust groove.

  Further, at the same time as or before or after the above process, an exhaust hole forming process for forming the first exhaust hole and the second exhaust hole in one glass substrate is performed. At this time, the first exhaust hole is formed so as to be positioned on the exhaust groove in the vicinity of the through hole when one glass substrate is superimposed on the side of the semiconductor substrate where the exhaust groove is formed. That is, the first exhaust hole is formed at a position as close as possible to each through hole. Further, when one glass substrate is overlaid on the side of the semiconductor substrate where the exhaust grooves are formed, a plurality of second through holes are formed along the communication grooves formed so as to surround the periphery of each through hole. .

  Then, after the above steps are completed, one glass substrate on which the first exhaust hole and the second exhaust hole are formed is bonded to one surface of the semiconductor substrate (the surface on which the exhaust groove is formed). At the same time, a bonding step of bonding the other glass substrate to the other surface is performed. By this joining step, the plurality of sensor portions formed on the semiconductor substrate are housed in a sealed chamber surrounded by the through hole and both glass substrates. However, at this time, each sealed chamber communicates with the outside through the exhaust groove, the communication groove, the first exhaust hole, and the second exhaust hole.

  After this joining process is completed, a vacuum process for evacuating the sealed chamber is performed. That is, a semiconductor substrate integrally bonded to both glass substrates is placed in a vacuum chamber and evacuated. At this time, as described above, each sealed chamber communicates with the outside through the exhaust groove, the communication groove, the first exhaust hole, and the second exhaust hole. Therefore, evacuation in each sealed chamber can be performed at the same time. In addition, since each sealed chamber is in communication with each other via the exhaust groove and the communication groove, the degree of vacuum of each sealed chamber tends to be in an equilibrium state. Therefore, even if there is some processing variation in each sealed chamber, exhaust groove, first exhaust hole, etc. due to the effect of processing accuracy, unlike the conventional one, the influence from such processing variation is directly affected. It is hard to receive. In other words, vacuuming can be performed by using the communication grooves communicating with all the sealed chambers, so even if there is some variation in processing accuracy, it is possible to perform vacuuming more positively than it is affected by these. The degree of vacuum can be made uniform. Therefore, variation in the degree of vacuum between chips (between each sealed chamber) can be minimized. In particular, since the communication groove is formed deeper than the exhaust groove, the flow path resistance is small and evacuation is easy. Therefore, not only can each vacuum chamber be surely evacuated to bring the degree of vacuum closer to a uniform state, but also the degree of vacuum can be increased. Furthermore, since the degree of vacuum is close to a certain level in a short time, the time for the vacuum process can be shortened and the production efficiency can be increased.

And after performing a vacuum process for a fixed time, the sealing process of vacuum-sealing each sealed chamber is performed. That is, a thin film is formed on the surface of one glass substrate by sputtering or vapor deposition in a vacuum. By this step, the inner peripheral surface of the first exhaust hole is also formed, and a thin film accumulates in the exhaust groove to close the first exhaust hole. Thereby, the path | route which connects each sealed chamber and the exterior can be closed, and each sealed chamber can be vacuum-sealed.
On the other hand, although the film is also formed on the inner peripheral surface of the second exhaust hole, since the communication groove is formed deeper than the exhaust groove, the thin film does not block the communication groove. Therefore, the second exhaust hole is not blocked unlike the first exhaust hole. Therefore, the surface of one glass substrate is not completely formed by a thin film, and is in a film formation state in which a hole is formed in the second exhaust hole portion. Therefore, the film stress can be reduced, and the one glass substrate can be prevented from being warped by the film stress as much as possible. As a result, quality can be improved.

Then, a cutting step is performed in which the semiconductor substrate and the two glass substrates that are integrally bonded together are cut by a cutting blade such as a dicing blade along the communication groove to be solidified. Thereby, the sealed mechanical quantity sensor in which the sensor unit is accommodated in the sealed chamber can be subdivided for each chip, and a plurality of them can be manufactured at a time.
In particular, it is possible to stably manufacture a plurality of mechanical quantity sensors of uniform quality at a time by minimizing the variation in the degree of vacuum between chips. Moreover, it is possible to efficiently manufacture a mechanical quantity sensor having improved vacuum and improved quality without warping or the like as compared with the prior art. Moreover, since it cut | disconnects along a communicating groove in the case of a cutting process, it only needs to cut | disconnect both glass substrates mainly. Therefore, the amount of cutting can be reduced, cutting performance can be improved, and the burden on the cutting blade can be reduced.

  The mechanical quantity sensor manufacturing method of the present invention is characterized in that, in the mechanical quantity sensor manufacturing method of the present invention, the communication groove is formed so as to penetrate the semiconductor substrate in the communication groove forming step. It is a feature.

In the method of manufacturing a mechanical quantity sensor according to the present invention, the communication groove is formed so as to penetrate the semiconductor substrate when the communication groove is formed, so that the depth of the communication groove can be maximized. Therefore, evacuation can be performed more easily, and variations in the degree of vacuum between the sealed chambers can be further eliminated. In addition, the degree of vacuum in the sealed chamber can be further improved, and the time required for the vacuum process can be shortened.
In this case, after joining one glass substrate, the process order may be partially changed so that the communication groove is formed from the other surface side of the semiconductor substrate.

  The mechanical quantity sensor manufacturing method of the present invention is characterized in that, in the mechanical quantity sensor manufacturing method of the present invention, the plurality of through-holes are formed so that the wall portion has a lattice shape in the sensor portion forming step. The second exhaust hole is formed in a state aligned in two directions along the plane direction of the semiconductor substrate, and the second exhaust hole is formed on a point where the communication groove formed in the wall portion is orthogonal in the exhaust hole forming step. A plurality of are formed.

In the manufacturing method of the mechanical quantity sensor according to the present invention, when forming the sensor portion on the semiconductor substrate, the plurality of through holes are formed in a state aligned in two directions (longitudinal direction and lateral direction) along the plane direction. . Thereby, the wall part surrounding the circumference | surroundings of each through-hole becomes a grid | lattice form. For this reason, the communication grooves formed in the wall portion also have a lattice shape. And in the case of an exhaust hole formation process, two or more 2nd exhaust holes are formed in one glass substrate so that a communicating groove may be located on the point which intersects perpendicularly. Therefore, the second exhaust holes can be evenly arranged with respect to the plurality of sealed chambers formed in an aligned state.
Therefore, since each vacuum chamber can be evacuated under the same conditions, variations in the degree of vacuum can be further reduced, and the quality can be more stably produced.

  Further, the mechanical quantity sensor manufacturing method of the present invention is the above-described mechanical quantity sensor manufacturing method of the present invention, wherein the exhaust groove and the communication groove intersect with each other in the exhaust hole forming step. The second exhaust hole is formed in a size including the exhaust hole.

  In the method of manufacturing a mechanical quantity sensor according to the present invention, the second exhaust hole is formed in a size including the first exhaust hole on the point where the exhaust groove and the communication groove intersect. That is, instead of forming the first exhaust hole and the second exhaust hole separately on one glass substrate, the second exhaust hole can also function as the first exhaust hole. The effect in this case is the same as the case where the first exhaust hole and the second exhaust hole are formed separately. In addition, since the number of exhaust holes formed in one glass substrate can be reduced, it is possible to prevent a decrease in strength of the glass substrate itself. Therefore, strength reliability can be improved. Moreover, since the strength reduction of the glass substrate can be prevented, the thickness of the glass substrate can be reduced, and further reduction in size and thickness can be achieved.

  Moreover, the manufacturing method of the mechanical quantity sensor of this invention is the manufacturing method of the mechanical quantity sensor of any one of the said invention, The said joining process is the said semiconductor substrate, said one glass substrate, and said other glass substrate. Are bonded by anodic bonding or room temperature bonding.

  In the method of manufacturing a mechanical quantity sensor according to the present invention, anodic bonding or room temperature bonding is performed during the bonding process. In particular, by performing commonly used anodic bonding, the semiconductor substrate and both glass substrates can be reliably bonded without using a special technique. In addition, when room temperature bonding is performed, it is not necessary to raise the temperature unlike anodic bonding, and bonding can be performed at room temperature. Therefore, unlike anodic bonding, oxygen gas due to temperature rise is not generated, and there is no possibility of lowering the degree of vacuum in the sealed chamber. Therefore, a more sensitive mechanical quantity sensor can be manufactured.

According to the method of manufacturing a mechanical quantity sensor according to the present invention, it is possible to stably manufacture a mechanical quantity sensor of uniform quality while minimizing variations in the degree of vacuum between chips .

Hereinafter, an embodiment of a mechanical quantity sensor, an electronic device, and a manufacturing method of a mechanical quantity sensor according to the present invention will be described with reference to FIGS.
In this embodiment, the electronic device is an electronic device 1 having a camera mechanism such as a digital camera or a mobile phone, and the mechanical quantity sensor is an angular velocity sensor (hereinafter referred to as a gyro sensor 2) that detects an angular velocity. Will be described below.

  FIG. 1 is a functional block diagram of an electronic device 1 in which the gyro sensor 2 of the present embodiment is incorporated. As shown in FIG. 1, the electronic device 1 includes a camera module 3 serving as a camera shake correction mechanism and a gyro sensor module 4 having the gyro sensor 2. The camera module 3 includes a lens correction amount calculation circuit 5 that calculates a correction amount of a camera lens (not shown) based on the angular velocity sent from the gyro sensor module 4, and a correction calculated by the lens correction amount calculation circuit 5. A lens driving circuit 8 that drives the X-axis lens actuator 6 and the Y-axis lens actuator 7 based on the amount is provided. Both lens actuators 6 and 7 can perform camera shake correction and the like by appropriately displacing the camera lens in the X and Y directions, respectively.

  The gyro sensor module 4 includes a gyro sensor 2, a CV conversion circuit 9 that converts a capacitance according to the angular velocity detected by the gyro sensor 2 into a voltage, and an angular velocity calculation that calculates an angular velocity from the converted voltage. Circuit 10. Further, the angular velocity calculation circuit 10 outputs the calculated angular velocity to the lens correction amount calculation circuit 5.

FIG. 2 is a cross-sectional view of the gyro sensor 2. As shown in FIG. 2, the gyro sensor 2 includes a silicon substrate (semiconductor substrate) 15, an upper glass substrate (one substrate) 16 and a lower glass substrate (the other substrate) which are joined in a state where the silicon substrate 15 is sandwiched from above and below. Substrate) 17. The thickness of the silicon substrate 15 and the glass substrates 16 and 17 is about 300 to 800 μm.
The silicon substrate 15 has a sensor unit 18 that is supported by a beam unit (not shown) and detects an angular velocity (mechanical quantity) applied from the outside. The sensor unit 18 is accommodated in a sealed chamber 20 surrounded by a through hole 19 formed in the silicon substrate 15 and an upper glass substrate 16 and a lower glass substrate 17. That is, the gyro sensor 2 is a sealed sensor in which the sensor unit 18 is accommodated in the sealed chamber 20.

  The gyro sensor 2 has an exhaust groove 21 that communicates between the sealed chamber 20 and the outside between the frame (wall portion) 15 a of the silicon substrate 15 and the upper glass substrate 16. However, the exhaust groove 21 is in a state of being blocked in the middle by the upper glass substrate 16 and a thin film 23 formed on the first exhaust hole 22 formed in the upper glass substrate 16. Thereby, the inside of the sealed chamber 20 is vacuum-sealed. That is, when the gyro sensor 2 is viewed from the side, the exhaust groove 21 can be confirmed between the silicon substrate 15 and the upper glass substrate 16, and the middle of the exhaust groove 21 is blocked by the thin film 23. Can be confirmed.

  The sensor unit 18 receives an electrostatic attraction from an electrode (not shown) in the sealed chamber 20 and vibrates at a predetermined frequency. When an angular velocity is received from the outside in this vibration state, the sensor unit 18 is twisted and displaced about the beam unit, and the distance from an electrode (not shown) is changed. The sensor unit 18 detects this change in distance as a change in capacitance and outputs it to the CV conversion circuit 9.

Next, a method for manufacturing the gyro sensor 2 configured as described above will be described below.
The manufacturing method of the present embodiment is a method for manufacturing a plurality of sealed gyro sensors 2 at a time using a single large silicon substrate 15 that is also a wafer substrate. This manufacturing method is manufactured by appropriately performing a sensor part forming step, an exhaust groove forming step, a communication groove forming step, an exhaust hole forming step, a joining step, a vacuum step, a sealing step, and a cutting step. It is a method to do.

  In the sensor part forming step, a plurality of through holes 19 surrounded by a frame 15 a are formed in the silicon substrate 15, and the sensor parts 18 are respectively formed so as to be disposed in the plurality of through holes 19. It is a process. The exhaust groove forming step is a step of forming the exhaust groove 21 with a predetermined depth on the surface of the silicon substrate 15 so as to connect the adjacent through holes 19 to each other. The communication groove forming step is a step of forming the communication groove 25 communicating with the exhaust groove 21 in the frame 15 a deeper than the exhaust groove 21 so as to surround the plurality of through holes 19. Further, in the exhaust hole forming step, when the upper glass substrate 16 is superimposed on the silicon substrate 15, the first glass substrate 16 is first exhausted so that the exhaust groove 21 communicates with the outside at least in the vicinity of the through hole 19. In this process, the holes 22 are formed and a plurality of second exhaust holes 24 are formed along the communication grooves 25 so that the communication grooves 25 communicate with the outside.

  The bonding step is a step of bonding the upper glass substrate 16 to one surface of the silicon substrate 15 in which the exhaust grooves 21 are formed and bonding the lower glass substrate 17 to the other surface of the silicon substrate 15. In addition, the vacuum process is a process in which the inside of the sealed chamber 20 is evacuated through the first exhaust hole 22, the second exhaust hole 24, the exhaust groove 21, and the communication groove 25 after the joining process. The sealing step is a step of vacuum-sealing the sealed chamber 20 by forming a thin film 23 on the surface of the upper glass substrate 16 in a vacuum. The cutting step is a step of cutting the integrally bonded silicon substrate 15 and the two glass substrates 16 and 17 along the communication groove 25 to separate them into a plurality of pieces.

  Each of these steps will be described in detail below with reference to FIGS. In addition, among each process mentioned above, each process except a vacuum process, a sealing process, and a cutting process may be performed simultaneously, and a process order is not limited. In the present embodiment, the case where the communication groove forming step is performed after the upper glass substrate 16 is first bonded to the silicon substrate 15 will be described as an example.

  FIG. 3 is a plan view of one large silicon substrate 15 that is also a wafer substrate as viewed from above. First, as shown in FIG. 3, a plurality of through holes 19 surrounded by a frame 15 a are formed on the silicon substrate 15 by a semiconductor processing technique such as lithography and etching, and a sensor is formed in each of these through holes 19. The sensor part formation process which forms the part 18 is performed. At this time, in this embodiment, the plurality of through holes 19 are arranged in two directions along the plane direction of the silicon substrate 15 (the vertical direction L1 and the horizontal direction L2 shown in FIG. 3) so that the frame 15a is formed in a lattice shape. Formed in an aligned state.

Next, an exhaust groove forming step for forming the exhaust grooves 21 on the surface of the silicon substrate 15 is performed. FIG. 4 is a plan view of the silicon substrate 15 after the exhaust groove 21 is formed from the state of FIG. 3 as viewed from above. FIG. 5 is a cross-sectional view taken along line AA shown in FIG.
As shown in FIGS. 4 and 5, the exhaust groove 21 is formed so as to connect the adjacent through holes 19. At this time, in the present embodiment, the exhaust groove 21 is formed so as to connect the through holes 19 adjacent in the lateral direction (L2 direction). However, the present invention is not limited to this, and the through holes 19 adjacent in the vertical direction (L1 direction) may be connected to each other, and adjacent to the two directions of the vertical direction (L1 direction) and the horizontal direction (L2 direction). The through holes 19 may be formed so as to be connected to each other. Further, when the exhaust groove 21 is formed, the exhaust groove 21 is formed to have a predetermined depth of several μm. By forming the exhaust groove 21 in the silicon substrate 15 in this way, each through hole 19 communicates with the adjacent through hole 19 through the exhaust groove 21 even when the upper glass substrate 16 is stacked on the silicon substrate 15. It becomes.

Next, an exhaust hole forming step for forming the first exhaust hole 22 and the second exhaust hole 24 in the upper glass substrate 16 is performed. FIG. 6 is a plan view of the upper glass substrate 16 as viewed from above after the silicon substrate 15 and the upper glass substrate 16 are overlaid. For easy understanding, the silicon substrate 15 has a communication groove 25 formed later.
As shown in FIG. 6, the first exhaust hole 22 is formed on the exhaust groove 21 in the vicinity of each through hole 19 when the upper glass substrate 16 is overlaid on the silicon substrate 15 on the side where the exhaust groove 21 is formed. Form so as to be positioned. Similarly, the second exhaust holes 24 are provided so as to be along communication grooves 25 described later when the upper glass substrate 16 is overlaid on the silicon substrate 15. Specifically, a plurality of communication grooves 25 are formed so as to be positioned on the orthogonal points. In addition, when forming the 1st exhaust hole 22 and the 2nd exhaust hole 24, it forms so that it may become a cross-sectional taper shape by sandblasting etc.

  Next, a bonding process for bonding the upper glass substrate 16 to the silicon substrate 15 first is performed. FIG. 7 is a view showing a state in which the upper glass substrate 16 is superimposed on the silicon substrate 15 after the state shown in FIG. As shown in FIG. 7, the upper glass substrate 16 in which the first exhaust holes 22 and the second exhaust holes 24 are formed is connected to one surface of the silicon substrate 15 (the surface on the side where the exhaust grooves 21 are formed). Then, the two substrates 15 and 16 are bonded by anodic bonding. As conditions for this anodic bonding, for example, the temperature is about 200 to 400 degrees and the voltage is 100 to 1000V.

Next, a communication groove forming step for forming the communication grooves 25 in the frame 15 a of the silicon substrate 15 blocking between the through holes 19 is performed. FIG. 8 is a plan view of the silicon substrate 15 after the communication groove 25 is formed from the state shown in FIG. 4 as viewed from above. 9 is a cross-sectional view taken along the line BB in FIG. 8 and shows a state after the communication groove 25 is formed from the state shown in FIG.
In the present embodiment, the communication groove 25 is formed by etching the substantially center of the frame 15a along the frame 15a so as to penetrate the silicon substrate 15 from the other surface side of the silicon substrate 15. Accordingly, as shown in FIGS. 8 and 9, each through hole 19 can be surrounded by the communication groove 25 and communicated with the exhaust groove 21 across the exhaust groove 21 connecting the adjacent through holes 19. The communication groove 25 can be formed. Note that the communication grooves 25 are formed in a lattice shape like the frame 15a.
The through-holes 19 are not only connected to the adjacent through-holes 19 via the exhaust grooves 21 by the communication grooves 25, but are also connected to the other through-holes 19 via the communication grooves 25 and the exhaust grooves 21. That is, all the through holes 19 are in a state of being in communication with each other via the communication groove 25 and the exhaust groove 21.

Next, a bonding process for bonding the lower glass substrate 17 to the silicon substrate 15 is performed. FIG. 10 is a diagram illustrating a state in which the lower glass substrate 17 is bonded after the state illustrated in FIG. 9. As shown in FIG. 10, after the lower glass substrate 17 is overlaid on the other surface of the silicon substrate 15, both substrates 15 and 17 are bonded by anodic bonding. The conditions for anodic bonding are the same as those for the upper glass substrate 16. Further, when the lower glass substrate 17 is bonded, the bonding process is completed.
By this step, the plurality of sensor portions 18 formed on the silicon substrate 15 are accommodated in a sealed chamber 20 surrounded by the through hole 19 and the glass substrates 16 and 17. However, at this time, each sealed chamber 20 communicates with the outside via the exhaust groove 21, the communication groove 25, the first exhaust hole 22, and the second exhaust hole 24.

  After the joining process is completed, a vacuum process for evacuating the sealed chamber 20 is performed. FIG. 11 is a view showing a state in which the silicon substrate 15 bonded to both the glass substrates 16 and 17 is placed in the chamber 30. As shown in FIG. 11, the silicon substrate 15 integrally bonded to both glass substrates 16 and 17 is put into a chamber 30 and evacuated. The chamber 30 is used when a sealing process is performed later by CVD. Therefore, a heater 30 a is incorporated in the chamber 30.

  Then, after setting in the chamber 30, evacuation is performed for a predetermined time. At this time, each sealed chamber 20 communicates with the outside via the exhaust groove 21, the communication groove 25, the first exhaust hole 22, and the second exhaust hole 24 as described above. Therefore, evacuation in each sealed chamber 20 can be performed simultaneously at the same time. In addition, since each sealed chamber 20 is in communication with each other via the exhaust groove 21 and the communication groove 25, the degree of vacuum of each sealed chamber 20 tends to be in an equilibrium state. Therefore, even if slight machining variations occur in each sealed chamber 20, exhaust groove 21, first exhaust hole 22, and the like due to the influence of machining accuracy, unlike the conventional ones, Not directly affected. In other words, since the evacuation can be performed using the communication grooves 25 communicating with all the sealed chambers 20, even if there is a slight variation in processing accuracy, the evacuation should be performed more positively than it is affected by these. The degree of vacuum of each sealed chamber 20 can be made uniform.

  Therefore, variation in the degree of vacuum between the chips (between the sealed chambers 20) can be minimized. In particular, since the communication groove 25 is formed deeper than the exhaust groove 21, the flow path resistance is small and it is easy to perform evacuation. Therefore, each sealed chamber 20 can be reliably evacuated to bring the degree of vacuum close to a uniform state, and the degree of vacuum can be increased. Furthermore, since the degree of vacuum is close to a certain level in a short time, the time for the vacuum process can be shortened and the production efficiency can be increased.

In particular, since the communication groove 25 is formed so as to penetrate the silicon substrate 15, it is a deeper groove than the exhaust groove 21. Therefore, evacuation can be performed more easily, and variations in the degree of vacuum between the sealed chambers 20 can be eliminated. Moreover, it is easy to improve the degree of vacuum and to shorten the time required for the vacuum process.
In addition, since the second exhaust holes 24 are evenly arranged with respect to the plurality of sealed chambers 20 formed in a state of being aligned in two directions of the vertical direction (L1 direction) and the horizontal direction (L2 direction). The vacuum chambers can be evacuated in a well-balanced condition under the same conditions. Also in this respect, the variation in the degree of vacuum can be reduced.
In addition, the effect mentioned above can show | play the same effect not only at the time of vacuum sealing but also when enclosing specific gas in the airtight chamber 20. FIG.

  After performing the said vacuum process for a fixed time, the sealing process of vacuum-sealing each sealed chamber 20 is performed. FIG. 12 is a view showing a state in which the thin film 23 is formed on the upper glass substrate 16 after the state shown in FIG. 13 is a cross-sectional view taken along the line CC shown in FIG. 6 after film formation. As shown in FIGS. 12 and 13, a thin film 23 is formed on the surface of the upper glass substrate 16 by a CVD method (Chemical Vapor Deposition) in a vacuum chamber 30. By this step, the inner peripheral surface of the first exhaust hole 22 is also formed, and the thin film 23 accumulates in the exhaust groove 21 to close the first exhaust hole 22. Thereby, the channel | path which connects each sealed chamber 20 and the exterior can be closed, and the inside of each sealed chamber 20 can be vacuum-sealed.

On the other hand, the thin film 23 is also formed on the inner peripheral surface of the second exhaust hole 24, but the communication groove 25 is formed deeper than the exhaust groove 21, so that the thin film 23 blocks the communication groove 25. There is no. FIG. 14 is a cross-sectional view taken along the line DD shown in FIG. 6 after film formation. As shown in FIG. 14, the thin film 23 only drops on the communication glass 25 and accumulates on the lower glass substrate 17. Therefore, unlike the first exhaust hole 22, the second exhaust hole 24 is not blocked. For this reason, the surface of the upper glass substrate 16 is not completely formed by the thin film 23 and is in a film formation state in which a hole is formed in the second exhaust hole 24. Therefore, the film stress can be reduced, and the upper glass substrate 16 can be prevented from being warped by the film stress as much as possible. As a result, unintended deformation can be prevented and quality can be improved.
Further, since the film stress can be reduced, even when TEOS (Tetra-Ethoxy-Silane), which is a material having high stress, is used when forming the thin film 23, the warp of the upper glass substrate 16 can be reduced. Therefore, film formation can be performed more firmly and vacuum sealing can be performed more reliably. As a result, the quality can be further improved.

  Finally, a cutting process is performed in which the silicon substrate 15 and the glass substrates 16 and 17 that are integrally joined together are cut along a communication groove 25 with a cutting blade (not shown) such as a dicing blade to be separated into pieces. Thereby, as shown in FIG. 2, the sealed gyro sensor 2 in which the sensor unit 18 is housed in the sealed chamber 20 can be subdivided for each chip, and a plurality can be manufactured at a time. In particular, since the cutting is performed along the communication groove 25 in the cutting process, it is only necessary to mainly cut both the glass substrates 16 and 17. Therefore, the amount of cutting can be reduced, cutting performance can be improved, and the burden on the cutting blade can be reduced.

  As described above, according to the manufacturing method of the present embodiment, it is possible to stably manufacture a plurality of gyro sensors 2 of uniform quality at a time while minimizing variations in the degree of vacuum between chips. In addition, it is possible to efficiently manufacture the gyro sensor 2 having a higher degree of vacuum than the prior art and improved quality without warping.

Next, a case where the angular velocity is detected by the gyro sensor 2 manufactured as described above and camera shake correction of the electronic device 1 is performed will be described.
First, a predetermined voltage is applied to an electrode (not shown) to generate an electrostatic attractive force, and the sensor unit 18 is excited with a predetermined input waveform. When an angular velocity is received from the outside in this excited state, the sensor unit 18 is twisted and displaced with the beam unit as a rotation center. As a result, the distance between the sensor unit 18 and the electrode changes. The sensor unit 18 detects this change in distance as a change in capacitance and outputs it to the CV conversion circuit 9.

  The CV conversion circuit 9 converts the sent capacitance change into a voltage and sends it to the angular velocity calculation circuit 10. The angular velocity calculation circuit 10 calculates an angular velocity from the converted voltage and outputs it to the lens correction amount calculation circuit 5 of the camera module 3. The lens correction amount calculation circuit 5 calculates the correction amount of the camera lens based on the calculated correction amount and outputs the calculated correction amount to the lens driving circuit 8. Then, the lens drive circuit 8 drives the X-axis lens actuator 6 and the Y-axis lens actuator 7 in a timely manner and displaces them in each direction based on the received correction amount. As a result, camera shake correction of the electronic device 1 can be performed.

  In particular, since the electronic device 1 of the present embodiment includes the above-described high-sensitivity and high-quality gyro sensor 2, the electronic device 1 itself can be improved in quality and performance.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above embodiment, the gyro sensor 2 has been described as an example of the mechanical quantity sensor. However, the gyro sensor 2 is not limited to the gyro sensor 2, and an acceleration sensor or the like may be used. Further, in the above embodiment, the case where the gyro sensor 2 is incorporated in the portable electronic device 1 such as a mobile phone having a camera mechanism has been described as an example, but not in such a small electronic device 1. The gyro sensor 2 of the present invention may be incorporated in a vehicle and used to activate an airbag.

  Further, in the communication groove forming step, the upper glass substrate 16 is bonded to one surface, and then the communication groove 25 is formed so as to penetrate the silicon substrate 15 from the other surface side. Instead, the communication groove 25 may be at least a groove deeper than the exhaust groove 21 (for example, a depth of several μm or more and several hundred μm or less). In this case, at the time of the exhaust groove forming step, the communication groove forming step may be simultaneously performed, and then the upper glass substrate 16 may be bonded.

  In the sealing process, the thin film 23 is formed by the CVD method. However, the thin film 23 may be formed by an evaporation method, a sputtering method, or the like. The material of the thin film 23 is not limited to TEOS, and any material can be selected as long as it can be formed. However, it is preferable to use TEOS because a strong film can be formed and the sealed chamber 20 can be vacuum-sealed more reliably.

  Moreover, in the said embodiment, although anodic bonding was performed when performing a joining process, you may join by normal temperature joining. In this case, bonding is performed by activating the surface using argon or the like in a high vacuum state, so that it is not necessary to raise the temperature unlike anodic bonding. That is, it is possible to bond at room temperature. Therefore, unlike anodic bonding, oxygen gas due to temperature rise is not generated, and there is no possibility of lowering the degree of vacuum in the sealed chamber 20. Therefore, the gyro sensor 2 with higher sensitivity can be manufactured.

  Moreover, in the said embodiment, although the 2nd exhaust hole 24 was formed so that the communication groove | channel 25 might be located on each orthogonal point, it is not restricted to this position, If it is on the communication groove 25, it forms in arbitrary positions. It doesn't matter. However, the second exhaust hole 24 is formed on the point where the communication grooves 25 are orthogonal to each other as in the above embodiment, so that the communication grooves 25 formed in the vertical direction (L1 direction) and the horizontal direction (L2 direction) are formed. Since the communication groove 25 formed in the above communicates with the outside through the second exhaust hole 24 in a well-balanced manner, vacuuming can be performed uniformly, which is preferable.

Here, a modified example of the second exhaust hole 24 will be described with reference to FIGS. 15 and 16. FIG. 15 is a plan view of the upper glass substrate 16 as viewed from above after the upper glass substrate 16 is overlaid on the silicon substrate 15 in which the exhaust grooves 21 and the communication grooves 25 are formed. 16 is a cross-sectional view taken along line EE shown in FIG. 15 after film formation.
As shown in FIG. 15, the second exhaust hole 24 may be formed in a size including the first exhaust hole 22 on the point where the exhaust groove 21 and the communication groove 25 intersect. That is, the first exhaust hole 22 and the second exhaust hole 24 are not separately formed in the upper glass substrate 16 as in the above embodiment, but the second exhaust hole 24 is formed in the first exhaust hole 22. It may be made to function as.

  Even if it does in this way, there can exist an effect similar to the said 1st Embodiment. That is, since each sealed chamber 20 communicates with the outside through the exhaust groove 21 and the communication groove 25 and communicates with the outside through the second exhaust hole 24, each sealed chamber 20 is uniformly evacuated. be able to. Therefore, variations in the degree of vacuum can be minimized. In addition, as shown in FIG. 16, when the sealing process is performed, the exhaust groove 21 is filled with the thin film 23, so that the inside of the sealed chamber 20 is sealed. On the other hand, since the communication groove 25 is deeper than the exhaust groove 21, it is not blocked by the thin film 23. Therefore, it is possible to prevent the upper glass substrate 16 from warping due to film stress, as in the above embodiment.

  Further, in the case of such a configuration, the number of exhaust holes formed in the upper glass substrate 16 can be reduced as compared with the case of the above embodiment. Therefore, strength reduction of the glass substrate itself can be prevented, and strength reliability can be further improved. Moreover, since the strength reduction of the glass substrate can be prevented, the thickness of the glass substrate can be reduced, and further reduction in size and thickness can be achieved.

In the above embodiment, the first exhaust hole 22 and the second exhaust hole 24 are formed in the upper glass substrate 16, but when the communication groove 25 is formed so as to penetrate the silicon substrate 15, The second exhaust hole 24 may be formed in the lower glass substrate 17.
FIG. 17 shows an upper glass substrate 16 in which a first exhaust hole 22 is formed, a lower glass substrate 17 in which a second exhaust hole 24 is formed, and a silicon substrate 15 in which an exhaust groove 21 and a communication groove 25 are formed. It is a figure which shows the state before joining.

  As shown in FIG. 17, a vacuum process may be performed after bonding the lower glass substrate 17 in which the second exhaust holes 24 are formed to the silicon substrate 15. Even in this case, the same effects as those of the above embodiment can be obtained. However, since the holes are formed in the glass substrates 16 and 17, respectively, it is preferable that the exhaust holes 22 and 24 are gathered in the upper glass substrate 16 in terms of the strength of the glass substrate.

It is a functional block diagram of the electronic device which has a gyro sensor which concerns on one Embodiment of this invention. It is sectional drawing of the gyro sensor shown in FIG. It is process drawing which showed the manufacturing method of the gyro sensor shown in FIG. 2, Comprising: While forming a several through-hole in the silicon substrate which is a wafer substrate, it is a top view which shows the state which formed the sensor part in this through-hole. is there. It is a figure which shows the state which formed the exhaust groove so that an adjacent through-hole might be tied after the state shown in FIG. It is sectional drawing along the AA line shown in FIG. FIG. 5 is a plan view seen from the upper glass substrate side after the silicon substrate shown in FIG. 4 and the upper glass substrate on which the first exhaust hole and the second exhaust hole are formed are overlaid. It is sectional drawing which looked at the state shown in FIG. 6 from the viewpoint of FIG. It is a figure which shows the state which formed the communicating groove | channel so that the circumference | surroundings of each through-hole might be enclosed after the state shown in FIG. It is sectional drawing along BB shown in FIG. It is a figure which shows the state which joined the lower glass substrate to the silicon substrate after the state shown in FIG. It is a figure which shows the state which put the silicon substrate joined to both the glass substrates in the chamber after the state shown in FIG. It is a figure which shows the state which formed the thin film on the upper glass substrate after the state shown in FIG. It is sectional drawing which looked at the state after the film-forming shown in FIG. 12 along CC line shown in FIG. It is sectional drawing which looked at the state after the film-forming shown in FIG. 12 along the DD line | wire shown in FIG. FIG. 10 is a diagram showing a modification of the second exhaust hole, and after the upper glass substrate on which the second exhaust hole having a size including the first exhaust hole is formed and the silicon substrate are overlaid, the upper glass substrate It is the top view seen from the side. It is sectional drawing which looked at the state after film-forming along the EE line | wire shown in FIG. FIG. 9 is a view showing a modification of the gyro sensor manufacturing method using the lower glass substrate in which the second exhaust hole is formed, and the upper glass substrate in which the first exhaust hole is formed and the second exhaust hole. It is a figure which shows the state immediately before joining the formed lower glass substrate and a silicon substrate. It is sectional drawing which shows an example of the conventional mechanical quantity sensor. FIG. 19 is a process diagram illustrating a manufacturing method of the mechanical quantity sensor illustrated in FIG. 18, after superposing the silicon substrate on which the sensor unit, the through hole and the exhaust groove are formed, and the glass substrate on which the exhaust hole is formed; It is the top view seen from the glass substrate side. It is sectional drawing along the FF line shown in FIG. It is the figure which looked at the state shown in FIG. 20 from the glass substrate side.

Explanation of symbols

1 Electronic equipment 2 Gyro sensor (mechanical quantity sensor)
15 Silicon substrate (semiconductor substrate)
15a frame (wall)
16 Upper glass substrate (one glass substrate)
17 Lower glass substrate (the other glass substrate)
DESCRIPTION OF SYMBOLS 18 Sensor part 19 Through-hole 20 Sealed chamber 21 Exhaust groove 22 1st exhaust hole 24 2nd exhaust hole 25 Communication groove

Claims (5)

Using a semiconductor substrate and one glass substrate and the other glass substrate bonded to both surfaces of the semiconductor substrate, a plurality of mechanical quantity sensors having a sensor unit for detecting a mechanical quantity acting from the outside are manufactured at a time. A method,
Forming a plurality of through-holes surrounded by wall portions in the semiconductor substrate, and forming each of the sensor portions so as to be disposed in the plurality of through-holes; and
An exhaust groove forming step of forming, at a predetermined depth, an exhaust groove connecting the adjacent through holes on the surface of the semiconductor substrate;
A communication groove forming step of forming a communication groove communicating with the exhaust groove so as to surround the plurality of through holes in the wall portion deeper than the exhaust groove;
A first exhaust hole is formed in the glass substrate so that the exhaust groove communicates with the outside at least in the vicinity of the through-hole when the one glass substrate is overlaid on the semiconductor substrate, and the communication groove An exhaust hole forming step of forming a plurality of second exhaust holes along the communication groove so as to communicate with the outside;
Bonding the one glass substrate to one surface of the semiconductor substrate in which the exhaust groove is formed, and bonding the other glass substrate to the other surface of the semiconductor substrate;
After the joining step, a vacuum step of evacuating the sealed chamber surrounded by the through hole and the first and second glass substrates through the communication groove and the exhaust groove;
After the vacuum step, a sealing step of forming a thin film on the surface of the one glass substrate in vacuum and vacuum sealing the sealed chamber;
After the sealing step, a cutting step of cutting the semiconductor substrate, the one glass substrate, and the second glass substrate that are integrally bonded along the communication groove into a plurality of pieces. A method for manufacturing a mechanical quantity sensor, comprising: In the manufacturing method of the mechanical quantity sensor of Claim 1,
The method of manufacturing a mechanical quantity sensor, wherein the communication groove is formed so as to penetrate the semiconductor substrate in the communication groove forming step. In the manufacturing method of the mechanical quantity sensor of Claim 1 or 2,
In the sensor portion forming step, the plurality of through holes are formed in a state aligned in two directions along the planar direction of the semiconductor substrate so that the wall portions are in a lattice shape,
In the exhaust hole forming step, a plurality of the second exhaust holes are formed on a point where the communication grooves formed in the wall portion are orthogonal to each other. In the manufacturing method of the mechanical quantity sensor of Claim 1 or 2,
In the exhaust hole forming step, the second exhaust hole having a size including the first exhaust hole is formed at a point where the exhaust groove and the communication groove intersect with each other. Manufacturing method. In the manufacturing method of the mechanical quantity sensor of any one of Claim 1 to 4,
The said joining process joins the said semiconductor substrate, said one glass substrate, and said other glass substrate by anodic bonding or normal temperature bonding, The manufacturing method of the mechanical quantity sensor characterized by the above-mentioned.

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