JP2002181845A - Semiconductor acceleration sensor, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor acceleration sensor of favorable productivity without generating a short circuit between electrodes in static capacity. SOLUTION: An opening part 18 is provided in part of a silicon substrate 1 composing a second layer to form such a constitution that a space forming a cavity 9 is connected to an external circuit through the opening part 18 only. The cavity 9 is a space between a fixed electrode plate 11 and the silicon substrate 1. In this constitution, a seal tape 17 is applied to close the opening part 18 in a process of separating and cutting the semiconductor acceleration sensor from a semiconductor wafer in manufacturing processes, and it is cut afterwards, so that invasion of cut chips or cutting water into the cavity 9 can be prevented. A process of inspecting if there is invasion of the chips or the cutting water or not, or a process of eliminating them can thus be dispensed with. A high reliability semiconductor acceleration sensor of improved productivity without having the short circuit between the electrodes in static capacity in the cavity 9 can thus be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a mass object, wherein an acceleration exerts a force on a mass object, and the force displaces a film-like portion on which the mass object is attached. The present invention relates to a semiconductor acceleration sensor that changes in capacitance and detects acceleration based on the change in capacitance, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A semiconductor acceleration sensor is a sensor manufactured by forming a plurality of components in a laminated structure on a semiconductor wafer in advance and separating and cutting the components in a later step. Since it can be manufactured in a small size and at a low cost, it is used as a component of various industrial machines. FIG. 8 is a schematic perspective view of a conventional semiconductor acceleration sensor. As shown in FIG. 8, it has a three-layer structure. That is, the first layer located below is the fixed electrode pedestal 10 and is made of a glass material that can be anodically bonded, and has a concave portion that forms a space for providing capacitance. The thickness of the fixed electrode base 10 is generally 0.5 to
The thickness is about 1 mm, but this thickness is for providing compactness. If it is necessary to increase the rigidity due to a load or the like, the thickness may be increased. The second layer located in the middle layer is a silicon substrate 1a having irregularities, and has a frame shape for providing rigidity around the periphery and a weight pedestal portion 5 for fixing and supporting the weight body 4 at the center. The periphery of 5 forms a concave portion formed by an etching process, and the bottom surface of the concave portion forms an extremely thin film portion 2. The general thickness of the silicon substrate 1a is 0.25 to 0.5 mm, and the general thickness of the film portion 2 is designed to be about several tens of μm. The third layer located on the upper layer is composed of the weight body 4 and an adhesive 13 for bonding the weight body 4 and the weight base 5.

The internal structure of a semiconductor acceleration sensor will be described with reference to FIGS. FIG. 9 is a view of the semiconductor acceleration sensor as viewed from above. When viewed through the first layer and the second layer, the fixed electrode plate 11 (shown by the dashed outer edge and the oblique lines in the figure) is disposed below these layers. The fixed electrode plate 11 is covered with the silicon substrate 1a as the second layer, but partially exposed upward (indicated by the solid line outer edge and the oblique line in the figure). At the upper left of the silicon substrate 1a, there is provided a contact electrode 6 for establishing electrical continuity between the silicon substrate 1a and an external circuit (not shown). FIG. 10 is a cross-sectional view taken along the center horizontal cross section XX of FIG. The fixed electrode plate 11 has an electrode pad 7 on an exposed portion upward, and is prepared for connection from above. The space between the lower part of the weight pedestal part 5 and the fixed electrode plate 11 is a so-called cavity 9 and has a capacitance according to the principle of a capacitor. Here, the principle of specifying the acceleration will be described. The film portion 2 can be deformed within the elastic limit, and when a force due to acceleration acts on the weight 4, the film portion 2 is displaced and the cavity 9 is deformed. The capacitance between the fixed electrode plate 11 and the silicon substrate 1a fluctuates according to this deformation, and the acceleration corresponding to this capacitance is specified. FIG. 11 is a diagram showing the bonding surface between the first layer and the second layer. The hatched area indicates the area where the silicon substrate 1a and the fixed electrode base 10 are anodically bonded. A substantially square at the center of the fixed electrode pedestal 10 is a concave portion in FIG. The recess formed so as to be drawn out on both sides of the cavity 9 is fixed electrode plate 1 so that the electrode pad 7 of the fixed electrode plate 11 is exposed.
1 is a drawer hole 14 for arranging 1.

Referring to FIG. 4, a description will be given of the fixed electrode plate 11 arranged in the concave portion of the fixed electrode base 10.
(A) is a figure which looked at the pedestal 10 for fixed electrodes from above,
(B), (c) is the figure which took out only the fixed electrode plate 11. FIG. As shown in (b) and (c), the fixed electrode plate 11 includes a counter electrode portion 11a, a lead portion 12, and an electrode pad 7. The cross-sectional configuration of the fixed electrode plate 11 is a two-layer structure in which the base is titanium and gold is provided on the upper part. As shown in (a), the fixed electrode plate 11 is arranged so that the opposing electrode portion 11a surrounds the region immediately below the film-shaped portion 2 from four directions.

FIG. 14 is a process chart showing a method for manufacturing a conventional semiconductor acceleration sensor. This semiconductor acceleration sensor includes a package base 100, a pedestal 110 made of an insulating substrate made of glass, a silicon substrate 101, a weight 104b, and a plurality of leads 100a provided on the package base 100.
And a bonding wire 103. The pedestal 110 corresponds to the fixed electrode pedestal 10 in FIG. Silicon substrate 10
1 corresponds to the silicon substrate 1a in FIG. The weight body 104b is
Like the weight body 4 in FIG. 8, it is made of silicon. Pedestal 110
Is provided with a planar electrode corresponding to the fixed electrode plate 11 in FIG. Pedestal 11 made of glass insulator substrate
A silicon substrate 101 is fixed to 0 to form an acceleration sensor chip. The weight body 104b is fixed to the acceleration sensor chip with an adhesive. As described above, the semiconductor acceleration sensor of FIG. 14 has the same configuration as the semiconductor acceleration sensor of FIG. 8 as a main part for acceleration detection, and the main part of the acceleration detection is mounted on the package base 100. In FIG. 14, the area denoted by reference numeral 110a is the area where the pedestal 110 is the silicon substrate 1
It is a portion that extends outside from 01 and is a region where an electrode pad is formed on the upper surface.

[0006] The conventional semiconductor acceleration sensor shown in FIG. 14 is manufactured in the order shown by (A), (B), (C) and (D) in FIG. As is apparent from this process chart, in the conventional method for manufacturing a semiconductor acceleration sensor, the electrode pad and the lead 100a on the pedestal 110 are connected to the bonding wire 10a.
The step of connecting by 3 is performed after the step of fixing the weight body 104b to the silicon substrate 101.

[0007]

As described above, the conventional semiconductor acceleration sensor uses the electrode pad 7 of the fixed electrode plate 11.
Since it is necessary to enable connection between the cavity 9 and an external circuit, a configuration in which the cavity 9 and the outside are spatially connected without being covered with the silicon substrate 1a is essential. However, in this configuration, in the manufacturing process of separating and cutting the individual semiconductor acceleration sensors from the semiconductor wafer, cutting powder and cutting water at the time of cutting may enter the cavity 9. It is difficult to determine and remove the infiltration of the cutting powder or cutting water because the sensor has a small and delicate structure, which requires an inspection step and a removal step, which leads to a reduction in production efficiency.

In the conventional method of manufacturing the acceleration sensor in the step of FIG. 14, the step of connecting the electrode pad and the lead 100a of the pedestal 110 with the bonding wire 103 fixes the weight body 104b to the silicon substrate 101. Performed after the process. Therefore, the weight body 104b cannot take a shape that is expanded in the lateral direction so as to protrude outside the pedestal 110. The sensitivity of the acceleration sensor improves as the mass of the weight body increases. In order to increase the mass of the weight body in a semiconductor acceleration sensor manufactured by a conventional method, as shown in FIG. 15A, a weight body 104c having an increased thickness in a direction perpendicular to the pedestal 110 is employed. Alternatively, it is conceivable to adopt a weight body 104d made of metal such as lead, which has a larger mass than silicon, as shown in FIG.

However, when the weight body 104c having an increased thickness as shown in FIG. 15A is employed, the height of the package needs to be increased, which is against the demand for miniaturization of the semiconductor acceleration sensor. When a metal weight 104d is employed as shown in FIG. 2B, the difference in the coefficient of thermal expansion between the metal weight 104d and the silicon silicon substrate 101 causes the silicon in the film portion to be different. Since the substrate 101 is subjected to a stress that fluctuates depending on the environmental temperature, the accuracy of detecting the acceleration is reduced and the stability of the accuracy of the detection is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object of the present invention is to provide a semiconductor acceleration sensor which has high productivity and has no fear of failure such as short-circuiting of electrodes in capacitance. It is in. A second object of the present invention is to provide a semiconductor acceleration sensor provided with a mass object (weight) having a shape expanded in the lateral direction so as to protrude outside the pedestal, and a method of manufacturing the same.

[0011]

The gist of the present invention to achieve the above object lies in the following inventions.

[1] The acceleration exerts a force on the weight body (4) and other mass objects, and the force causes a displacement in the film portion (2) provided with the mass object, and the displacement causes the film shape. The capacitance between the part (2) and the opposing electrode changes,
In a semiconductor acceleration sensor for detecting the acceleration based on a change in the capacitance, a first pedestal of the electrode (11) is formed.
The electrode (1) comprises a layered structure including at least a layer (10) and a second semiconductor layer (1a) for holding a gap (9) providing the capacitance between the electrode (11).
1) has a lead portion (12) for connection to the outside, and the second layer (1a) has an opening (18) for enabling connection between the lead portion (12) and an external circuit. , The opening (1)
8) A semiconductor acceleration sensor having a flat surface at the periphery.

[2] The second layer (1a) is the film-like portion (2)
And a weight base (5), wherein the weight base (5) is provided.
Is disposed in a central region of the film-like portion (2), and a weight body (4) is mounted on the weight pedestal portion (5), and the weight body (4) is attached to the second layer. (1a) The semiconductor acceleration sensor according to [1], wherein the semiconductor acceleration sensor includes a third layer laminated on the third layer.

[3] The semiconductor acceleration sensor according to [1] or [2], wherein the plane of the periphery of the opening (18) is located at the highest position in the second layer (1a). .

[4] The acceleration exerts a force on the weight body (4) and other mass objects, and the force causes a displacement in the film portion (2) provided with the mass object, and the displacement causes the film shape. The capacitance between the portion (2) and the opposing electrode (11) changes, and a plurality of semiconductor acceleration sensors for detecting the acceleration based on the change in the capacitance are formed on a semiconductor wafer, and the semiconductor acceleration sensor is cut and separated by a cutting / separating step. In the method for manufacturing a semiconductor acceleration sensor using the semiconductor acceleration sensor as a chip, the semiconductor acceleration sensor includes a first layer (10) serving as a base of the electrode (11) and a gap (9) for providing the capacitance. A second semiconductor layer (1a) held between the first electrode and the electrode (11);
And at least one of the electrodes (1
1) has a lead portion (12) for connection to the outside, and the second layer (1a) has an opening (18) for enabling connection between the lead portion (12) and an external circuit. , The opening (1)
8) has a flat surface at the peripheral edge, and covers the opening (18) with a seal tape, thereby sealing and blocking the space including the gap (9) from the outside. And removing the sealing tape after the cutting and separation.

[5] The acceleration exerts a force on the weight body (4) and other mass objects, causing a displacement in the film portion (2) provided with the mass object by the force, and the displacement causes the film shape. The capacitance between the portion (2) and the opposing electrode (11) changes, and a plurality of semiconductor acceleration sensors for detecting the acceleration based on the change in the capacitance are formed on a semiconductor wafer, and the semiconductor acceleration sensor is cut and separated by a cutting / separating step. In the method for manufacturing a semiconductor acceleration sensor using the semiconductor acceleration sensor as a chip, the semiconductor acceleration sensor includes a first layer (10) serving as a pedestal for the electrode (11) and a gap (9) for providing the capacitance. A second semiconductor layer (1a) held between the first electrode and the electrode (11);
And at least one of the electrodes (1
1) has a lead portion (12) for connection with the outside, and the second layer (1a) has the film-like portion (2) and a weight pedestal portion (5).
And an opening (18) for enabling connection between the drawer (12) and an external circuit, wherein the weight pedestal (5) is disposed in a central region of the film-like portion (2). A weight body (4) is mounted on the weight pedestal (5), and the weight body (4) is a third layer laminated on the second layer (1a). The opening (18) has a flat surface at a peripheral edge, and covers the opening (18) with a seal tape (17), thereby sealingly shutting off a space including the gap (9) from the outside, and opening the seal tape (17). A) performing the cutting / separating step after adhering, and removing the sealing tape (17) after the cutting / separating step.

[6] The peripheral flat surface of the opening (18) is flush with the upper surface of the weight pedestal portion (5) or higher than the upper surface of the weight pedestal portion (5).
7) The method for manufacturing a semiconductor acceleration sensor according to [4] or [5], wherein a temporary fixing tape (8) for temporarily fixing the semiconductor wafer is also used in the cutting and separating step.

[7] The acceleration exerts a force on the weight body (4) and other mass objects, and the force causes a displacement in the film portion (2) provided with the mass object, and the displacement causes the film shape. The capacitance between the portion (2) and the opposing electrode (11) changes, and a plurality of semiconductor acceleration sensors for detecting the acceleration based on the change in the capacitance are formed on a semiconductor wafer, and the semiconductor acceleration sensor is cut and separated by a cutting / separating step. In the method for manufacturing a semiconductor acceleration sensor using the semiconductor acceleration sensor as a chip, the semiconductor acceleration sensor includes a first layer (10) serving as a base of the electrode (11) and a gap (9) for providing the capacitance. A second semiconductor layer (1a) held between the first electrode and the electrode (11);
And at least one of the electrodes (1
1) has a lead portion (12) for connection to the outside, and the second layer (1a) has an opening (18) for enabling connection between the lead portion (12) and an external circuit. The opening (18) has a flat surface on the periphery, and the flat surface on the periphery of the opening (18) is located at the highest position in the second layer (1a), and the semiconductor wafer is temporarily fixed to the tape ( 8) The semiconductor device, wherein the cutting and separating step is performed in a state where the opening is covered with the temporary fixing tape (8) and the space including the gap (9) is sealed off from the outside. Manufacturing method of acceleration sensor.

[8] The acceleration exerts a force on the weight body (4) and other mass objects, and the force causes a displacement in the film portion (2) provided with the mass object. The capacitance between the portion (2) and the opposing electrode (11) changes, and a plurality of semiconductor acceleration sensors for detecting the acceleration based on the change in the capacitance are formed on a semiconductor wafer, and the semiconductor acceleration sensor is cut and separated by a cutting / separating step. In the method for manufacturing a semiconductor acceleration sensor using the semiconductor acceleration sensor as a chip, the semiconductor acceleration sensor includes a first layer (10) serving as a base of the electrode (11) and a gap (9) for providing the capacitance. A second semiconductor layer (1a) held between the first electrode and the electrode (11);
And at least one of the electrodes (1
1) has a lead portion (12) for connection with the outside, and the second layer (1a) has the film-like portion (2) and a weight pedestal portion (5).
And an opening (18) for enabling connection between the drawer section (12) and an external circuit, wherein the weight pedestal section (5) is disposed in a central region of the film section (2). A weight body (4) is mounted on the weight pedestal portion (5), and the weight body (4) is a third layer laminated on the second layer (1a). The opening (18) has a plane at the periphery, and the plane of the periphery of the opening (18) is at the highest position in the second layer (1a), and the semiconductor wafer is temporarily fixed to the temporary fixing tape. And a step of covering the opening (18) with the temporary fixing tape and performing the cutting / separating step in a state where the space including the gap is hermetically sealed from the outside.

[9] An acceleration sensor chip in which a semiconductor substrate is fixed to a base made of an insulator made of glass or the like, a mass object fixed to the semiconductor substrate, and the acceleration sensor chip with the mass object A package to be mounted, the pedestal is provided with a planar electrode, the semiconductor substrate has a film portion, and the film portion faces the electrode with a small gap. A weight pedestal portion for fixing the mass object is provided at a central portion of the film-shaped portion, and the mass object is fixed to the weight pedestal portion by fixing means such as an adhesive. In a semiconductor acceleration sensor in which the electrodes are electrically connected by bonding wires, an outer edge of the mass object viewed from a direction perpendicular to the planar electrode extends outward from an outer edge of the pedestal viewed in the same direction. And The semiconductor acceleration sensor, characterized in that.

[10] An acceleration sensor chip having a semiconductor substrate fixed to a pedestal made of an insulating substrate such as glass;
A mass body fixed to the semiconductor substrate, and a package on which the acceleration sensor chip with the mass body is mounted, wherein the pedestal is provided with a planar electrode, and the semiconductor substrate has a film-like shape. Portion, the film-shaped portion faces the electrode with a small gap, a weight pedestal portion for fixing the mass object is provided at the center of the film-shaped portion, and the mass object is The mass pedestal is fixed to the weight pedestal portion with an adhesive or the like, and the lead of the package and the electrode are electrically connected by a bonding wire, and the mass object is viewed from a direction perpendicular to the planar electrode. A first step of fixing the semiconductor substrate to the pedestal to form a pedestal with a semiconductor substrate, wherein the outer edge is wider than the outer edge of the pedestal as viewed from the same direction; substrate A second step of fixing the base to the base of the package, a third step of connecting the electrode and the lead with the bonding wire, and a fourth step of fixing the mass object to the weight base. And a method of manufacturing a semiconductor acceleration sensor.

[0022]

FIG. 6 is a schematic perspective view of a semiconductor acceleration sensor according to an embodiment of the present invention. The silicon substrate 1 of the present embodiment is larger than the silicon substrate 1a of the conventional example shown in FIG. 8, and the extraction hole 14 formed in the fixed electrode pedestal 10 does not protrude and is exposed as in the conventional example. Are all covered with the silicon substrate 1. In addition, the silicon substrate 1 has two openings 18 through which the electrode pads 7 of the fixed electrode plate 11 are exposed upward to enable connection with an external circuit.
Further, the periphery of the opening of the opening 18 is formed as a flat surface, and has a configuration in which a seal tape can be attached. The configuration of the semiconductor acceleration sensor according to the present embodiment is the same as that of the conventional semiconductor acceleration sensor except for the portion related to the opening 18 described above, and the principle of specifying the acceleration is the same. FIG. 2 is a diagram of the semiconductor acceleration sensor according to the present embodiment as viewed from above. The fixed electrode plate 11 is configured to be exposed upward only through the opening 18. FIG. 3 is a sectional view taken along the center horizontal section XX of FIG. An opening 18 is provided above the electrode pad 7 as compared with FIG.
Is formed. The structure of the first layer is exactly the same as that of the conventional example shown in FIG. 10, and a diagram viewed from above is shown in FIG. FIG. 5 is a diagram showing the bonding surface between the first layer and the second layer. The hatched area indicates the area where the silicon substrate 1 and the fixed electrode pedestal 10 are anodically bonded. Opening 18
Is a non-joining area due to space, and a part of the extraction hole 14 is exposed upward in the opening 18.

The cutting / separating step in the manufacturing steps of the semiconductor acceleration sensor according to the present embodiment will be described with reference to FIG. (A) is a sectional view showing a semiconductor acceleration sensor formed on a semiconductor wafer before cutting, and (b) is a sectional view showing a state during cutting. Since the components of the sensor are formed sequentially from the lower layer as shown in FIG.
The fixed electrode pedestal 10 as the layer and the silicon substrate 1 as the second layer are connected to each other for each sensor. It is the cutting separation process that cuts this connection at the chip boundary 15 into one chip. As a process before cutting, the opening 18 on the electrode pad 7 is closed by attaching a seal tape 17 as shown in FIG. By this processing, the space from the cavity 9 to the opening 18 is cut off from the outside. Next, the semiconductor wafer is temporarily fixed to a dicing tape ((b)
The dicing tape is omitted in FIG. 1), and the wafer is cut along the chip boundary 15 by a dicing saw 16. Thereafter, the seal tape 17 is peeled off to obtain individual semiconductor acceleration sensors.

Referring to FIG. 7, another embodiment of the present invention will be described. In the case where the seal tape attachment margin on the periphery of the opening 18 is the same as the height of the upper surface of the weight pedestal or higher than the height of the upper surface of the weight pedestal (this embodiment is different from the weight pedestal 5 in the previous embodiment in order to distinguish it). The weight pedestal in the form is represented as 5a), and as shown in FIG. 7, the weight pad 4 can be temporarily fixed to the dicing tape 8 with the exposed surface of the electrode pad 7 facing down without the weight body 4 bonded thereto. Thus, the opening 18 can be sealed simultaneously with the temporary fixing of the semiconductor wafer. Therefore, it is possible to omit the sealing tape 17 and the step of attaching the sealing tape 17 which are required in the above embodiment. After cutting and separating, the semiconductor acceleration sensor can be obtained by peeling the chip from the dicing tape 8 and bonding the weight 4.

When the weight pedestal 5a is designed to have such a weight as to be able to receive the action of the force due to acceleration, the weight 4 becomes unnecessary. In this case, there is no step of attaching the weight body 4 after the cutting and separation described in the other embodiment. The embodiments of the present invention described in claims 1 to 8 have been described above.

Next, an embodiment of the present invention described in claims 9 and 10 will be described. FIG. 12 is a view showing a semiconductor acceleration sensor of the embodiment, and FIG. 13 is a process chart showing a method for manufacturing the semiconductor acceleration sensor of FIG. This semiconductor sensor includes a package base 100, a pedestal 110 made of an insulating substrate made of glass, a silicon substrate 101, and a weight body.
The package includes a plurality of leads 104a provided on the package base 100, and a plurality of bonding wires 103. The pedestal 110 corresponds to the fixed electrode pedestal 10 in FIG. The silicon substrate 101 corresponds to the silicon substrate 1a in FIG. The weight body 104a is made of silicon, like the weight body 4 in FIG. The fixed electrode plate 11 in FIG.
Are provided. A silicon substrate 101 is fixed to a pedestal 110 made of a glass insulator substrate to constitute an acceleration sensor chip. The weight body 104a is fixed to the acceleration sensor chip with an adhesive. As described above, the semiconductor acceleration sensor of FIG. 12 has a configuration similar to that of the semiconductor acceleration sensor of FIG. 8 as a main part for acceleration detection, and the main part of the acceleration detection is mounted on the package base 100. In FIGS. 12 and 13, a region indicated by reference numeral 110a is a portion where the pedestal 110 extends outside the silicon substrate 101, and is a region where an electrode pad is formed on the upper surface.

The conventional semiconductor acceleration sensor of FIG. 12 is manufactured in the order shown in FIGS. 13 (A), (B), (C) and (D). As is apparent from this process diagram, in this method of manufacturing a semiconductor acceleration sensor, the electrode pad and the lead 100a on the pedestal 110 are connected to the bonding wire 103.
The step (C) of connecting the weight 104a to the silicon substrate 10
This is performed before the step (D) of fixing to 1. Therefore, the semiconductor acceleration sensor shown in FIG. 12 can be manufactured even if a weight body 104a that extends outward from the pedestal 110 and extends to almost the same level as the mounting surface (upper surface) of the package base 100 is used. it can.

Therefore, even if the weight body 104a has the same thickness as the conventional one, the weight body 104a can take a shape expanded in the lateral direction so as to protrude outside the pedestal 110, so that the mass can be increased as compared with the conventional one. As a result, the sensitivity of the acceleration sensor can be improved. As described above, by employing the weight body 104a expanded in the lateral direction, the center of gravity G
Does not increase, the height of the package needs to be increased, and the coefficient of thermal expansion between the weight body 104a and the silicon substrate 101 does not differ. Therefore, the semiconductor acceleration sensor of FIG. 12 can improve the acceleration detection sensitivity without lowering the acceleration detection accuracy and the stability of the detection accuracy, and has solved the drawbacks of the conventional structure illustrated in FIG.

[0029]

According to the semiconductor acceleration sensor of the present invention described in claims 1 to 8, an opening is provided in a part of the silicon base constituting the second layer, and only through the opening,
A configuration in which the space forming the cavity is connected to the outside is adopted. Thus, in the process of separating and cutting the semiconductor acceleration sensor from the semiconductor wafer during the manufacturing process, a sealing tape is applied so as to cover such an opening, and then cut to prevent cutting powder and cutting water from entering the cavity. can do. Further, the present invention proposes a configuration in which the height of the plane of the periphery of the opening is the highest in the second layer. With these configurations, the opening can be set to the dicing tape side in the processing before the cutting and separating step, and the semiconductor wafer can be temporarily fixed so as to cover the opening with the dicing tape. Thus, the process of temporarily fixing the semiconductor wafer and the process of closing the opening can be performed in one step, and the cost can be significantly reduced.

Further, as described in the embodiments with reference to FIGS. 12 and 13, the present invention described in claims 9 and 10 has a shape which is expanded in the lateral direction so as to protrude outside the pedestal. Provided are a semiconductor acceleration sensor having a mass object (weight body) and a method of manufacturing the same. By employing this semiconductor acceleration sensor, the acceleration detection sensitivity can be improved without lowering the acceleration detection accuracy and the stability of the detection accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a cutting and separating step in a manufacturing step of a semiconductor acceleration sensor according to an embodiment of the present invention.

FIG. 2 is a plan view of the semiconductor acceleration sensor according to the embodiment as viewed from above.

FIG. 3 is a cross-sectional view taken along a center horizontal cross section XX of FIG. 2;

FIG. 4 is a plan view of the fixed electrode base 10 according to the embodiment and the conventional example as viewed from above.

FIG. 5 is a diagram illustrating a bonding surface between a first layer and a second layer according to the embodiment.

FIG. 6 is a schematic perspective view of a semiconductor acceleration sensor according to the embodiment.

FIG. 7 is a view illustrating a cutting / separating step in a manufacturing step of a semiconductor acceleration sensor according to another embodiment of the present invention.

FIG. 8 is a schematic perspective view of a conventional semiconductor acceleration sensor.

FIG. 9 is a plan view of a conventional semiconductor acceleration sensor viewed from above.

FIG. 10 is a cross-sectional view taken along a center horizontal cross section XX of FIG. 9;

FIG. 11 is a diagram illustrating an adhesive surface between a first layer and a second layer of a conventional semiconductor acceleration sensor.

FIG. 12 is a diagram showing a configuration of a semiconductor acceleration sensor according to another embodiment of the present invention.

FIG. 13 is a process chart showing a method for manufacturing the semiconductor acceleration sensor of FIG.

FIG. 14 is a process chart showing a method for manufacturing a conventional semiconductor acceleration sensor.

FIG. 15 is a diagram illustrating a configuration of a conventional semiconductor acceleration sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Silicon substrate 1a ... Silicon substrate 2 ... Film part 4 ... Weight body 5 ... Weight pedestal part 5a ... Weight pedestal part 6 ... Contact electrode 7 ... Electrode pad 8 ... Dicing tape 9 ... Cavity 10 ... Fixed electrode pedestal 11 ... fixed electrode plate 11a ... counter electrode part 12 ... lead part 13 ... adhesive 14 ... lead-out hole 15 ... chip boundary 16 ... dicing saw 17 ... seal tape 18 ... opening part 100 ... package base part 100a ... package base part 100 Lead 103 provided on the bonding wire 110 pedestal

Claims (10)

[Claims] An acceleration exerts a force on a weight body or another mass object, and a displacement is generated by the force in a film-like portion provided with the mass object, and the displacement causes a displacement between an electrode facing the film-like portion. In a semiconductor acceleration sensor that detects the acceleration by a change in the capacitance between the first layer and the first layer that forms the base of the electrode, a gap that provides the capacitance is formed between the electrode and the first layer. The electrode has a lead portion for connection to the outside, and the second layer enables connection between the lead portion and an external circuit. A semiconductor acceleration sensor having an opening, wherein the opening has a flat surface at a periphery. 2. The second layer has the film portion and a weight pedestal portion, wherein the weight pedestal portion is disposed in a central region of the film portion, and a weight body is provided on the weight pedestal portion. 2. The semiconductor acceleration sensor according to claim 1, wherein the weight body is a third layer stacked on the second layer. 3. 3. The semiconductor acceleration sensor according to claim 1, wherein a plane of a periphery of the opening is located at a highest position in the second layer. 4. An acceleration exerts a force on a weight body or other mass object, and a displacement is caused by the force on a film portion provided with the mass object. A semiconductor acceleration sensor for detecting the acceleration based on a change in the capacitance between the semiconductor acceleration sensor and a plurality of semiconductor acceleration sensors, and manufacturing the semiconductor acceleration sensor using the semiconductor acceleration sensor as a chip by a cutting and separating process In the method, the semiconductor acceleration sensor comprises a stacked structure including at least a first layer forming a pedestal of the electrode, and a second semiconductor layer holding a gap providing the capacitance between the first layer and the second layer. The electrode has a lead portion for connection to the outside, the second layer has an opening for connecting the lead portion and an external circuit, and the opening has a flat surface at a peripheral edge. , Previous By covering the opening with a seal tape, the space including the gap is sealed off from the outside, the cutting and separating step is performed after the sealing tape is attached, and the sealing tape is removed after the cutting and separating. Manufacturing method of a semiconductor acceleration sensor. 5. The acceleration exerts a force on a weight body or another mass object, and the force causes a displacement in a film-like portion provided with the mass object, and the displacement causes a displacement between the film-like portion and an electrode facing the film-like portion. A semiconductor acceleration sensor for detecting the acceleration based on a change in the capacitance between the semiconductor acceleration sensor and a plurality of semiconductor acceleration sensors, and manufacturing the semiconductor acceleration sensor using the semiconductor acceleration sensor as a chip by a cutting and separating process The method according to claim 1, wherein the semiconductor acceleration sensor has a stacked structure including at least a first layer serving as a base of the electrode and a second semiconductor layer holding a gap that provides the capacitance between the first layer and the electrode. The electrode has a lead portion for connection to the outside, and the second layer has the film-like portion, a weight pedestal portion, and an opening for enabling connection between the lead portion and an external circuit. And before A weight pedestal is disposed in a central region of the film-shaped portion, a weight is mounted on the weight pedestal, and the weight is a third layer laminated on the second layer. The opening has a flat surface at the periphery, and the opening is covered with a seal tape, thereby sealingly shutting off the space including the gap from the outside, and performing the cutting and separating step after attaching the seal tape, The method for manufacturing a semiconductor acceleration sensor, wherein the sealing tape is removed after the cutting and separating. 6. A plane of a periphery of the opening is higher than an upper surface of the weight pedestal portion or higher than an upper surface of the weight pedestal portion, and the seal tape temporarily fixes the semiconductor wafer in the cutting and separating step. The method for manufacturing a semiconductor acceleration sensor according to claim 4, wherein the temporary fixing tape is also used. 7. The acceleration exerts a force on a weight body or other mass object, and a displacement is caused by the force on a film portion provided with the mass object. A semiconductor acceleration sensor for detecting the acceleration based on a change in the capacitance between the semiconductor acceleration sensor and a plurality of semiconductor acceleration sensors, and manufacturing the semiconductor acceleration sensor using the semiconductor acceleration sensor as a chip by a cutting and separating process The method, wherein the semiconductor acceleration sensor comprises a first electrode seating the electrode.
A laminated structure including at least a layer and a second semiconductor layer that holds a gap that provides the capacitance between the electrode and the electrode, the electrode having a lead portion that connects to the outside, The second layer has an opening that allows connection between the lead-out portion and an external circuit, the opening has a flat surface at a periphery, and a flat surface at the periphery of the opening is highest in the second layer. Position, the semiconductor wafer is temporarily fixed to the temporary fixing tape, the opening is covered with the temporary fixing tape, and the cutting and separating step is performed in a state where the space including the gap is sealed off from the outside. A method for manufacturing a semiconductor acceleration sensor. 8. The acceleration exerts a force on a weight body or other mass object, and the force causes a displacement in a film-like portion provided with the mass object, and the displacement causes a displacement between an electrode facing the film-like portion. A semiconductor acceleration sensor for detecting the acceleration based on a change in the capacitance between the semiconductor acceleration sensor and a plurality of semiconductor acceleration sensors, and manufacturing the semiconductor acceleration sensor using the semiconductor acceleration sensor as a chip by a cutting and separating process The method, wherein the semiconductor acceleration sensor comprises a first electrode seating the electrode.
A laminated structure including at least a layer and a second semiconductor layer that holds a gap that provides the capacitance between the electrode and the electrode, the electrode having a lead portion that connects to the outside, The second layer has the film-shaped portion, a weight pedestal portion, and an opening that allows connection between the drawer portion and an external circuit, and the weight pedestal portion is disposed in a central region of the film-shaped portion. A weight body is mounted on the weight pedestal portion; the weight body is a third layer laminated on the second layer; the opening has a flat surface at a periphery; The plane of the periphery of the opening is at the highest position in the second layer, the semiconductor wafer is temporarily fixed to the temporary fixing tape, the opening is covered with the temporary fixing tape, and the space including the gap is externally fixed. Performing the cutting / separating step in a state of being sealed off from the semiconductor. Method of manufacturing a capacitor. 9. An acceleration sensor chip having a semiconductor substrate fixed to a base made of an insulator made of glass or the like, a mass object fixed to the semiconductor substrate, and the acceleration sensor chip with the mass object mounted thereon. Wherein the pedestal is provided with a planar electrode, the semiconductor substrate has a film-like portion, and the film-like portion faces the electrode with a small gap, A weight pedestal portion for fixing the mass object is provided at a center portion of the film-shaped portion, and the mass object is fixed to the weight pedestal portion by fixing means such as an adhesive. In a semiconductor acceleration sensor in which electrodes are electrically connected by bonding wires, an outer edge of the mass object viewed from a direction perpendicular to the planar electrode extends outward from an outer edge of the pedestal viewed from the same direction. Being A semiconductor acceleration sensor characterized by the above-mentioned. 10. An acceleration sensor chip comprising a semiconductor substrate fixed to a base made of an insulator made of glass or the like, a mass object fixed to the semiconductor substrate, and the acceleration sensor chip with the mass object mounted thereon. Wherein the pedestal is provided with a planar electrode, the semiconductor substrate has a film-like portion, and the film-like portion faces the electrode with a small gap, A weight pedestal portion for fixing the mass object is provided at a center portion of the film-shaped portion, and the mass object is fixed to the weight pedestal portion by fixing means such as an adhesive. Manufacturing of a semiconductor acceleration sensor in which electrodes are electrically connected by bonding wires, and an outer edge of the mass object viewed from a direction perpendicular to the planar electrode extends outside an outer edge of the pedestal viewed from the same direction. How to smell A first step of fixing the semiconductor substrate to the pedestal to form a pedestal with a semiconductor substrate; a second step of fixing the pedestal with the semiconductor substrate to a base of the package; and the electrode and the lead And a fourth step of fixing the mass object to the weight pedestal portion.