JP3275698B2 - Manufacturing method of semiconductor acceleration sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor acceleration sensor used for automobiles, aircrafts, home electric appliances, and the like.

[0002]

2. Description of the Related Art Conventionally, a method of manufacturing a semiconductor acceleration sensor of this type will be described with reference to FIGS. In this manufacturing method, in the sensing element forming step, based on the weight portion A, a bending portion B having one end connected to the weight portion A so that the weight portion A bends when acceleration is applied thereto, and a bending portion B A sensor portion C formed on a bending portion B so as to convert acceleration into an electric signal;
A plurality of sensing elements each including: a support portion D that surrounds and surrounds the first portion 1 with a space to support the other end of the bending portion B; and an electrode pad E connected to the sensor portion C on one surface side of the support portion D. Is formed on a silicon wafer F.

Next, in a stopper fixing step, a stopper G having a contact surface G1 with which the weight portion A can contact is fixed to one surface side of the silicon wafer F, and an opening H is formed in the stopper G.
At the corresponding position of the electrode pad E.

More specifically, in the inspection step, after the stopper fixing step, the electrode pad E is shielded by the stopper G. Therefore, before the stopper fixing step in which the electrode pad E is exposed, that is, in the sensing element forming step. After that, the electrical characteristics of the sensor section C were inspected by bringing the inspection needle into contact with the electrode pad E.

[0005]

In the above-described conventional method for manufacturing a semiconductor acceleration sensor, a semiconductor having a cantilever structure in which one end of a flexure B is connected to a weight A and the other end is supported by a support D. An acceleration sensor can be manufactured.

However, since the electrical characteristics of the sensor portion C change due to the stress caused by the fixing of the stopper G, the inspected electric characteristics change after the fixing of the stopper G. In the inspection, it is necessary to break the natural oxide film of the electrode pad E to obtain electrical continuity. Therefore, the probe needle, that is, the inspection needle is pressurized while being in contact with the electrode pad E at an angle, and the electrode pad E is pressed. It is performed by sliding while scratching the surface. Therefore, the inspection needle has an inclination of about 50 degrees with respect to the plane.

Here, it is desirable that the inspection is performed after the stopper H that shields the electrode pad E is provided with the opening H and the stopper is fixed without changing the electrical characteristics.
When the inspection is performed by contacting the inspection needle with the electrode pad E after the stopper is fixed, if the width of the opening H provided in the stopper G is not sufficient, the inspection needle contacts the side wall of the stopper G corresponding to the opening H. As a result, the test needle cannot be brought into contact with the electrode pad E. If the opening H is made wider to solve this problem, the area occupied by the sensing elements in the silicon wafer F becomes large, resulting in a problem that the cost increases.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sensor after a stopper fixing step without increasing the area occupied by a sensing element in a silicon wafer as compared with the related art. It is an object of the present invention to provide a method of manufacturing a semiconductor acceleration sensor capable of accurately inspecting a part.

[0009]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor acceleration sensor, comprising: a weight portion; and one end of which is bent so as to be bent when acceleration is applied to the weight portion. A flexure connected to the flexure, a sensor formed in the flexure to convert the acceleration into an electric signal based on the flexure of the flexure, and an outer peripheral edge of the weight provided with a space to surround the flexure. A plurality of pairs of sensing elements each including a support portion for supporting the other end and an electrode pad connected to the sensor portion on one surface side of the support portion are arranged such that both electrode pads of each pair have a predetermined distance from each other. A sensing element forming step formed on the silicon wafer in an adjacent state on the side, and then a stopper fixing step of fixing a stopper having a contact surface with which a weight portion can contact to one surface side of the silicon wafer; S Tsu contacting a test needle electrode pad exposed to an opening provided in the path, it is then configured to have an inspection step of inspecting the electrical characteristics of the sensor unit.

According to a second aspect of the present invention, in the method for manufacturing a semiconductor acceleration sensor according to the first aspect, in the step of forming the sensing element, the test electrodes connected to each of the pair of electrode pads are arranged in a line. In the inspection step, the inspection needle is brought into contact with the inspection electrode in the inspection step to perform inspection.

According to a third aspect of the present invention, there is provided a method of manufacturing a semiconductor acceleration sensor based on a weight, a flexure having one end connected to the weight so as to flex when acceleration is applied to the weight, and a flexure of the flexure. A sensor portion formed on the bending portion to convert the acceleration into an electric signal, a supporting portion for providing a space around the outer peripheral edge of the weight portion and supporting the other end of the bending portion, Element forming step in which a plurality of sensing elements each having an electrode pad connected to a sensor unit are formed on a silicon wafer in a state where inspection electrodes connected to the respective electrode pads are integrated at a predetermined position on one surface side. And a stopper fixing step of fixing a stopper having an abutting surface to which the weight can abut on one surface side of the silicon wafer, and then an inspection electrode exposed at an opening provided in the stopper. Are a configuration having a inspection step of inspecting the electrical characteristic of the sensor unit contacts the test needle.

According to a fourth aspect of the present invention, in the method of manufacturing a semiconductor acceleration sensor according to the first or third aspect, the stopper fixing step includes fixing the stopper provided with the opening in advance.

According to a fifth aspect of the present invention, in the method of manufacturing a semiconductor acceleration sensor according to the first or third aspect, the opening of the stopper is formed such that the opening area is increased toward the opening. .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 3 shows a manufacturing process diagram. First, in a sensing element forming step, a silicon wafer 11 having an N-type conductivity is used (a), and an impurity is diffused on one surface side of the silicon wafer 11 at a predetermined position where a bent portion 12 is formed. A sensor portion 13 is formed by providing a P-type piezoresistor (b). Sensor unit 13
(C) forming a silicon nitride film 11a on both sides of the silicon wafer 11,
The silicon nitride film 11a on the other surface is removed at the outer peripheral edge of the weight portion 14 and at a position corresponding to the bent portion 12 (d), and the silicon wafer 11 is etched from the other surface to form a concave portion 14a. And thinning the silicon wafer 11 at a position corresponding to the outer peripheral edge of the weight portion 14 (e).

The silicon nitride film 11a on one side is provided at a position corresponding to the silicon nitride film 11a on the other side and the wiring resistance portion 13a.
Are respectively removed (f), and an electrode pad 15 connected to the sensor section 13 via the wiring resistance section 13a on one surface side is formed (g). Of the thinned portion in which the concave portion 14a is formed, only the portion where the sensor portion 13 is formed is left, and the other portion is etched by reactive ion etching in which the other portion is etched in a certain direction, and the weight portion 14 and the bent portion are formed. 1
A support 16 for supporting the other end of the second 2 is formed (h). In this manner, the sensing element 1 having a cantilever structure in which the bending portion 12 has one end connected to the weight portion 14 and the other end supported by the support portion 16 is formed.

Here, a plurality of pairs of the sensing elements 1 are in a state where both electrode pads 15, 15 of each pair 1a, 1b are adjacent to each other at a predetermined distance on one surface side of the silicon wafer 11, ie, each pair. Pair sensing element 1
a, 1b are formed on the silicon wafer 11 with both electrode pads 15, 15 facing each other so as to be adjacent to each other (i).

Next, in a stopper fixing step, the stopper 2 is fixed to one surface side of the silicon wafer 11. Here, the stopper 2 is made of a substantially square glass,
Abutment surface 2 on which one surface 4 can abut on one surface side of silicon wafer 11
a, a space is provided between the contact surface 2 a and the weight portion 14. Further, when a groove is formed for forming the contact surface 2a, the opening 2 provided with the notch 2c is formed.
b is formed so that the opening area becomes wider toward the opening side. The stopper 2 is fixed so that the electrode pad 15 of the sensing element 1 is located at the opening 2b (j).

Another stopper 21 is made of substantially rectangular glass, and has another contact surface 21a with which the weight portion 14 can contact on the other surface of the silicon wafer 11. Fixed on the side.

Next, in the inspection step, the inspection needle 3 is attached to the electrode pad 15 exposed in the opening 2b provided in the stopper 2.
Are contacted with each other to inspect the electrical characteristics of the sensor unit 13. Finally, in a separation step, a plurality of pairs of the sensing elements 1 formed on the silicon wafer 11 are separated to complete the semiconductor acceleration sensor. Here, the stopper 2 and another stopper 21 are applied with excessive acceleration. Then, the weight portion 14 abuts on the contact surface 2a or another contact surface 21a to prevent the flexible portion 12 from being broken by excessive deformation. Also, the weight portion 14
The so-called air damping effect due to the viscosity of the air in the space between the two prevents damage at the resonance frequency and optimizes the distance between the weight portion 14 and the contact surface 2a and another contact surface 21a. To improve the frequency response.

The operation of the semiconductor acceleration sensor will be described. When acceleration is applied to the weight portion 14, the weight portion 14 is displaced in a direction opposite to the direction in which the acceleration is applied, and the bending portion 12 bends, and the sensor portion 13 formed on one surface of the bending portion 12 is deformed. The resistance value of the sensor unit 13, that is, the piezoresistor changes. The acceleration is detected by measuring the resistance value of the piezoresistor.

In the method of manufacturing the semiconductor acceleration sensor according to the first embodiment, as described above, in the sensing element forming step, both electrode pads 15, 15 of each pair 1a, 1b of a plurality of pairs of sensing elements are provided.
Competitors are formed on the silicon wafer 11 so as to be adjacent to each other with a predetermined distance on one side, and the stopper 2 is fixed to the one side of the silicon wafer 11 in a stopper fixing step. Since the electrical characteristics of the sensor unit 13 are inspected by contacting the electrode pad 15 exposed in the opening 2b wider than in the conventional case, the area occupied by the sensing element 1 in the silicon wafer 11 is not increased compared to the conventional case. After the stopper fixing step in which the electric characteristics are stable, the electric characteristics of the sensor unit 13 are accurately inspected to improve the pass / fail judgment rate, and the semiconductor acceleration sensor can be manufactured.

In addition, since the stopper 2 provided with the opening 2b previously formed at the same time as the contact surface 2a in the stopper fixing step is fixed to one surface of the silicon wafer 11, it is necessary to provide the opening 2b after the fixing. It is not necessary to form a kerf in the stopper 2, and it is possible to manufacture without damaging the electrode pad 15 due to the kerf forming process.

The opening 2b of the stopper 2 is formed such that the opening area becomes wider toward the opening, so that the inclined inspection needle 3 does not contact the side wall of the opening 2b of the stopper 2 and the inspection needle 3 is connected to the electrode. The inspection can be performed by contacting the pad 15.

In the first embodiment, the opening 2b is formed so that the opening area becomes wider toward the opening.
Is not in contact with the side wall of the stopper 2 of the opening 2b, it does not have to be formed so as to be wider as the opening side, and there is no limitation.

In the first embodiment, the stopper 2 is provided with the notch 2c in the opening 2b so that the opening area becomes wider toward the opening, but the single crystal silicon wafer 11 having a specific orientation is selected instead of glass. After the silicon wafer 11 is coated with a silicon nitride film, a silicon oxide film, or the like, the silicon wafer 11 may be anisotropically etched, and the angle of the etching wall surface may be inclined so that the opening area becomes larger toward the opening side, but is not limited thereto.

In the first embodiment, in the stopper fixing step, the stopper 2 provided with the opening 2b is fixed to one surface of the silicon wafer 11, but as shown in FIG. In (a), a cut groove is formed in a portion of the stopper 2 corresponding to the electrode pad 15 to open the opening 2b.
May be formed (b), and there is no limitation.

A second embodiment of the present invention will be described below with reference to FIGS. In the second embodiment, functions different from those in the first embodiment will be described, and members having substantially the same functions as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

In the sensing element forming step,
Inspection electrodes 17 are provided in a row on one surface side of the silicon wafer 11, and each pair of sensing elements 1 a,
Each of the two electrode pads 15 of 1b is wired and connected with a material such as aluminum. Next, in the stopper fixing step, the stopper 2 is fixed so that the electrode pad 15 and the inspection electrode 17 of the sensing element 1 are located in the opening 2b. Next, in the inspection process, the inspection needle 3 is inclined and brought into contact with the inspection electrode 17 exposed in the opening 2 b provided in the stopper 2, and the electrical characteristics of the sensor unit 13 are inspected.

Finally, in the separation step, separation lines for separating each of a plurality of pairs of the sensing elements 1 formed on the silicon wafer 11 are provided in the line of the inspection electrodes 17. A plurality of sensing elements 1 formed on the silicon wafer 11 with the stopper 2 fixed thereto
Is separated by this separation line to complete the semiconductor acceleration sensor. In the manufacturing method of the semiconductor acceleration sensor according to the second embodiment, as described above, in the sensing element forming step, the inspection electrodes 17 are Are connected to the two electrode pads 15, 15 of the sensing elements 1a, 1b, respectively, and are provided in a line. Therefore, in the inspection process, the inspection needle 3 is not the electrode pad 15, but the inspection electrode 1.
7, the electrical characteristics of the sensor section 13 are inspected by contacting the inspection needle 3, and the electrode pads 15 are not damaged. Therefore, bonding the electrode pads 15 reduces bonding defects due to the scratches. Can be manufactured. further,
Separation lines for separating each of a plurality of pairs of the sensing elements 1 formed on the silicon wafer 11 are provided in the line of the inspection electrodes 17, so that the area of the sensing elements 1 on the silicon wafer 11 by the inspection electrodes 17 is increased. Can be prevented.

The opening 2b of the stopper 2 is formed such that the opening area becomes wider toward the opening, so that the inspection needle 3 can be inspected without the inclined inspection needle 3 coming into contact with the side wall of the opening 2b of the stopper 2. Inspection can be performed by contacting the electrode 17 for use. A third embodiment of the present invention will be described below with reference to FIGS. Note that in the third embodiment, the first
Functions different from those of the first embodiment will be described, and members having substantially the same functions as those of the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

In the step of forming the sensing element,
The plurality of sensing elements 1 are connected to the respective electrode pads 15 using a material such as aluminum or the like.
7 are formed on the silicon wafer 11 in an integrated state at a predetermined position provided for inspection on one side of the silicon wafer 11.

Next, in the stopper fixing step, the stopper 2 is fixed so that the electrode pad 15 of the sensing element 1 and the inspection electrode 17 are located in the opening 2b. Next, in the inspection process, the inspection needle 3 is inclined and brought into contact with the inspection electrode 17 exposed in the opening 2 b provided in the stopper 2, and the electrical characteristics of the sensor unit 13 are inspected.

In the method of manufacturing the semiconductor acceleration sensor according to the third embodiment, as described above, in the sensing element forming step, a plurality of sensing elements 1 are connected to the test electrodes 17 connected to the respective electrode pads 15. Are formed on the silicon wafer 11 in a state where they are integrated at a predetermined position on one side, and the stopper 2 is formed in the stopper fixing step.
Is fixed to one surface side of the silicon wafer 11, and in the inspection process, the electrical characteristics of the sensor portion 13 are inspected by contacting the inspection electrode 17 exposed in the opening 2b. Thus, the electrical characteristics of the plurality of sensing elements 1 can be simultaneously and accurately inspected by only raising the inspection needle 3 once, so that the time required for the inspection process can be reduced, and the semiconductor acceleration sensor can be manufactured.

In addition, since the stopper 2 provided with the opening 2b previously formed at the same time as the contact surface 2a in the stopper fixing step is fixed to one surface of the silicon wafer 11, it is necessary to provide the opening 2b after the fixing. It is not necessary to form a kerf in the stopper 2, and it is possible to manufacture without damaging the electrode pad 15 due to the kerf forming process.

Since the opening 2b of the stopper 2 is formed so that the opening area becomes wider toward the opening, the inspection needle 3 is inspected without the inclined inspection needle 3 coming into contact with the side wall of the opening 2b of the stopper 2. Inspection can be performed by contacting the electrode 17 for use.

[0036]

According to the first aspect of the present invention, in the method of manufacturing a semiconductor acceleration sensor, in the sensing element forming step, both electrode pads of each pair of the plurality of sensing elements are adjacent to each other at a predetermined distance on one surface side. Is formed on a silicon wafer in a state, and a stopper is fixed to one surface side of the silicon wafer in a stopper fixing step.
Since the inspection needle contacts the electrode pad exposed in the opening wider than the conventional one and inspects the electrical characteristics of the sensor part, the area occupied by the sensing element in the silicon wafer is not increased, and the electrical After the stopper fixing step in which the characteristics are stable, the electrical characteristics of the sensor portion are accurately inspected to improve the pass / fail judgment rate, whereby the semiconductor acceleration sensor can be manufactured.

According to a second aspect of the present invention, in addition to the effect of the first aspect of the present invention, in the sensing element forming step, the inspection electrodes are formed on the two electrode pads of each pair of the sensing elements. In the inspection process, the inspection needle is brought into contact with the inspection electrode instead of the electrode pad to inspect the electrical characteristics of the sensor section, and the inspection needle damages the electrode pad. Since the electrode pads are not attached, bonding defects due to scratches can be reduced by bonding the electrode pads.

According to a third aspect of the present invention, in the method of manufacturing a semiconductor acceleration sensor, in the sensing element forming step, a plurality of sensing elements are integrated with a test electrode connected to each electrode pad at a predetermined position on one surface side. Formed on the wafer, the stopper is fixed to one side of the silicon wafer in the stopper fixing step, and in the inspection step, the electrical characteristics of the sensor part are inspected by contacting the inspection electrode exposed in the opening. After the stable stopper fixing process, the electrical characteristics of a plurality of sensing elements can be simultaneously and accurately inspected by only raising the inspection needle once,
The time required for the inspection process can be reduced, and the semiconductor acceleration sensor can be manufactured.

According to a fourth aspect of the present invention, in addition to the effect of the first or third aspect, an opening formed at the same time as the contact surface in the stopper fixing step is provided in advance. Since the stopper is fixed to the one surface side of the silicon wafer, it is possible to eliminate damage to the electrode pad caused by making a groove in the stopper after the fixing.

In the method of manufacturing a semiconductor acceleration sensor according to the fifth aspect, in addition to the effect of the manufacturing method of the first or third aspect, the opening of the stopper is formed so that the opening area becomes wider toward the opening. The inspection needle can be brought into contact with the electrode pad or the inspection electrode without the inspection needle coming into contact with the opening side wall of the stopper.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a manufacturing process diagram of the same.

FIG. 4 is a manufacturing process diagram of the same stopper fixing process.

FIG. 5 is a sectional view showing a second embodiment of the present invention.

FIG. 6 is a plan view of the same.

FIG. 7 is a sectional view showing a third embodiment of the present invention.

FIG. 8 is a plan view of the same.

FIG. 9 is a sectional view showing a conventional example.

FIG. 10 is a plan view of the same sensing element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensing element 11 Silicon wafer 12 Flexure part 13 Sensor part 14 Weight part 15 Electrode pad 16 Support part 17 Inspection electrode 2 Stopper 2a Contact surface 2b Opening 3 Inspection needle

Claims (5)

(57) [Claims] A weight portion, a bending portion having one end connected to the weight portion to bend when acceleration is applied to the weight portion, and a bending portion for converting acceleration into an electric signal based on bending of the bending portion. The formed sensor portion, a support portion that provides a space around the outer peripheral edge of the weight portion and supports the other end of the bending portion, and an electrode pad connected to the sensor portion on one surface side of the support portion. A sensing element forming step in which a plurality of pairs of the provided sensing elements are formed on a silicon wafer in a state in which the two electrode pads of each pair are adjacent to each other at a predetermined distance on one surface side, and A stopper fixing step of fixing a stopper having an abutting surface to one surface side of the silicon wafer, and then contacting an inspection needle with an electrode pad exposed in an opening provided in the stopper to inspect electric characteristics of the sensor unit. Inspection The method of manufacturing a semiconductor acceleration sensor and having a step. 2. In the sensing element forming step, test electrodes connected to each of the pair of electrode pads are provided in a line, and the test needle is attached to the test electrode in the test step. The method for manufacturing a semiconductor acceleration sensor according to claim 1, wherein the inspection is performed by contact. 3. A weight portion, a bending portion having one end connected to the weight portion to bend when acceleration is applied to the weight portion, and a bending portion for converting acceleration into an electric signal based on the bending of the bending portion. The formed sensor portion, a support portion that provides a space around the outer peripheral edge of the weight portion and supports the other end of the bending portion, and an electrode pad connected to the sensor portion on one surface side of the support portion. A sensing element forming step of forming a plurality of sensing elements on a silicon wafer in a state where test electrodes connected to respective electrode pads are integrated at a predetermined position on one surface side; and A stopper fixing step of fixing a stopper having a contact surface to one surface side of the silicon wafer, and then, a test needle is brought into contact with a test electrode exposed at an opening provided in the stopper to test the electrical characteristics of the sensor unit. The method of manufacturing a semiconductor acceleration sensor comprising: the inspection process, the that. 4. The method for manufacturing a semiconductor acceleration sensor according to claim 1, wherein the stopper fixing step includes fixing a stopper provided with the opening in advance. 5. The method for manufacturing a semiconductor acceleration sensor according to claim 1, wherein the opening of the stopper is formed such that the opening area becomes wider toward the opening.