JPH06324076A - Semiconductor acceleration sensor - Google Patents

Abstract

PURPOSE:To cut a stopper gap in a semiconductor acceleration sensor smaller in width, to avoid break during cutting and to shorten the cutting time, and further to make bonding easy. CONSTITUTION:A weight body 15 and a controlling member 19 are formed in a structure of a double layer consisting of a first glass layer 16 and a second silicon layer 17. The first layer 16 is set at the side to be bonded to a diaphragm member 10 of silicon and a stopper gap 21 is formed in the second layer 17. The bonding part is formed of silicon and glass. Moreover, the stopper gap 21 is easy to cut by a dicing saw and formed of silicon showing a small cutting resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor acceleration sensor.

[0002]

2. Description of the Related Art As one of the prior arts related to the present invention, there is a sensor using a resistance element described in JP-A-4-84725. This is, as shown in FIG. 6, a semiconductor pellet 4 made of silicon in which a fixing portion 3 is formed with a working portion 1 in the central portion and a flexible portion 2 around the working portion 1,
A weight body 5 made of glass or silicon that is suspended and held by the central portion of the upper surface of the semiconductor pellet 4 being joined to the action portion 1 of the semiconductor pellet 4 is provided. A pedestal 6 made of the same material as the weight body 5 joined to the fixed portion 3, and a stopper gap 7 having a predetermined width formed between a side portion of the weight body 5 and a side portion of the pedestal 6 facing the weight body 5. , A control board 8 joined to the lower surface of the pedestal 6,
The acceleration is detected by detecting the strain of the semiconductor pellet 4 due to the displacement of the weight body 5 caused by the acting acceleration by utilizing the piezo effect.

Such a sensor is manufactured as follows. First, the weight 5 and the pedestal 6 are defined by forming a wide groove 9 from the upper surface to the lower surface of the base material that constitutes the weight 5 and the pedestal 6 with a dicing saw. To do. Next, while the weight body 5 and the pedestal 6 are not separated, their upper surfaces are bonded to the working portion 1 and the fixing portion 3 of the semiconductor pellet 4, respectively, and thereafter,
The weight body 5 and the pedestal 6 are separated by cutting and forming a stopper gap 7 having a predetermined width from the lower surface of the base material with a dicing saw.
It is held suspended in the air. The stopper gap 7 functions as a stopper of the weight body 5 in order to prevent the semiconductor pellet 4 from being excessively deformed and damaged when an excessive acceleration is applied, and is a few from the viewpoint of improving impact resistance. A width of 10 μm is required.

[0004]

In the above prior art, glass or silicon is used as the base material forming the weight body and the pedestal. When glass is used as the base material, since glass that can be bonded to silicon is a difficult-to-cut material for a dicing saw, not only is it extremely difficult to cut a stopper gap having a width of several tens of μm, The cutting also requires an extremely long time. According to an experiment by the present inventor, 0.1 mm / se is used for cutting the stopper gap.
It has been confirmed that it takes about c time. Further, since glass has a large cutting resistance, there is a problem that vibration during cutting is transmitted to the semiconductor pellet through the weight body during cutting of the stopper gap, and the semiconductor pellet may be damaged. On the other hand, when silicon is used as the base material,
While easy to cut, the semiconductor pellet and the weight and the pedestal are bonded to each other by silicon, and the anodic bonding method cannot be used, which makes bonding extremely difficult compared to the case of silicon and glass. was there.

The present invention has been made based on the above viewpoint, and an object thereof is to be able to cut a stopper gap having a smaller width, to prevent damage during cutting and to shorten the cutting time. Moreover, it is to provide a semiconductor acceleration sensor that can be easily joined.

[0006]

SUMMARY OF THE INVENTION In the present invention, a diaphragm member made of silicon having a working portion at the central portion and a fixing portion formed around the working portion via a flexible portion, and the central portion of one surface are A weight body that is joined to an acting portion of the diaphragm member and is suspended and held; a restricting member that is spaced apart from the outer periphery of the weight body and has one surface joined to the fixing portion of the diaphragm member; In a semiconductor acceleration sensor having a stopper gap of a predetermined width formed between a side part of the body and a side part of the limiting member facing the side part,
A two-layer structure in which a base material forming the weight body and the limiting member is made of glass and a second layer made of silicon is joined, and the first layer is joined to the diaphragm member. On the side, the weight body and the limiting member are respectively joined to the acting portion and the fixing portion of the diaphragm member, and the semiconductor acceleration sensor in which the stopper gap having the predetermined width is formed in the second layer is used. Achieve the purpose.

[0007]

The weight body and the limiting member have a two-layer structure of a first layer made of glass and a second layer made of silicon, and the first layer made of glass serves as a diaphragm member made of silicon. A stopper gap is formed in the second layer which is joined and made of silicon. The diaphragm member, the weight body, and the limiting member are made of silicon and glass, and can be easily joined by the anodic joining method. Since the stopper gap is formed in the second layer made of silicon that is easy to cut by the dicing saw and has a small cutting resistance, it is possible to cut the stopper gap having a smaller width, for example, about 10 μm, which is not possible with glass. The impact resistance can be greatly improved, and moreover, damage can be prevented during cutting, and
The cutting time can be greatly reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing an embodiment of the present invention.

In FIG. 1, reference numeral 10 denotes a diaphragm member made of silicon, and a groove 11 formed by etching or the like on the lower surface thereof has a thick action portion 12 at the central portion.
However, a thin flexible portion 13 is formed around the acting portion 12, and a thick fixing portion 14 is formed around the flexible portion 13. The acting portion 12 of the diaphragm member 10 is the flexible portion 1
The bending of 3 causes it to be displaced with respect to the fixed portion 14. A weight body 15 is suspended and held on the lower surface of the acting portion 12 of the diaphragm member 10.

The weight body 15 includes a first layer 16 made of glass and a second layer 1 made of silicon that can be bonded to silicon.
7 has a two-layer structure bonded to each other, and is provided with the first layer 16 made of glass facing upward. The peripheral portion of the weight body 15 is formed lower by etching or the like so that the central portion of the upper surface of the weight body 15 has a convex shape, and a bonding surface 18 is provided at the central portion of the convex shape. The weight body 15 is the joint surface 1
8 is joined to the lower surface of the acting portion 12 of the diaphragm member 10 to be suspended and held by the diaphragm member 10. Around the weight body 15 like this, the weight body 1
A limiting member 19 that surrounds 5 is provided.

The limiting member 19 has a weight 1 as will be described later.
Since it is formed separately from the same base material as that of No. 5, like the weight body 15, a two-layer structure in which a first layer 16 made of glass and a second layer 17 made of silicon that can be joined to silicon are joined. In the structure, the weight 15 is provided so that the first layer 16 made of glass faces upward. The upper surface of the limiting member 19 is joined to the lower surface of the fixed portion 14 of the diaphragm member 10. A separating groove 20 and a stopper gap 21 communicating with the separating groove 20 are formed between the limiting member 19 and the weight body 15. The separation groove 20 is a wide groove formed from the upper surface to the lower surface of the first layer 16 and separates the first layer 16 into the limiting member 19 and the weight body 15. The stopper gap 21 is formed from the upper surface to the lower surface of the second layer 17 made of silicon, and separates the second layer 17 into the limiting member 19 and the weight body 15. The stopper gap 21 has a function of limiting the displacement of the weight body 15 in the plane direction according to the acceleration, and is set to a desired width.

Reference numeral 22 is a substrate provided below the limiting member 19 and the weight body 15. The lower surface of the second layer 17 forming the weight body 15 and the limiting member 19 should not hinder the displacement of the weight body 15 when the peripheral portion of the upper surface of the substrate 22 is joined to the lower surface of the limiting member 19. The recess 17a is formed. The peripheral portion of the upper surface of the substrate 22 is joined to the lower surface of the limiting member 19, and the displacement of the weight body 15 is not hindered through the recess 17a.

The semiconductor acceleration sensor having the above structure is manufactured according to the steps shown in FIGS.

2, FIG. 3, FIG. 4 and FIG. 5 are manufacturing process drawings of the semiconductor acceleration sensor having the structure shown in FIG. 1. FIG. 2 is a first process, FIG. 3 is a second process, and FIG. 4 is a third process. FIG. 5 shows the fourth step. The same reference numerals as those in FIG. 1 indicate the same elements.

First, in the first step of FIG. 2, the first layer 16 made of glass and the second layer 17 made of silicon are joined by the anodic bonding method to form the weight body 15 and the limiting member 19. A base material 30 having a two-layer structure is formed. Since the first layer 16 and the second layer 17 are bonded to glass and silicon, they can be bonded easily by the anodic bonding method. The recess 31 is formed on the surface of the first layer 16 made of glass of the base material 30 by etching or the like, whereby the diaphragm member 1
The joint surface 18 of the weight body 15 with respect to 0 and the limiting member 19
The joint surface 32 of is formed. Further, a recess 17a for preventing displacement of the weight body 15 is formed on the lower surface of the second layer 17 made of silicon of the base material 30 by etching or the like. Since the recess 17a is formed in the second layer 17 made of silicon, it can be easily formed as compared with the case where it is formed in glass. Next, in a second step of FIG. 3, a separation groove 20 is formed in the first layer 16 made of glass by a dicing saw, and the weight body 15 and the limiting member 19 are defined. Since the separation groove 20 is a wide groove as described in the description of the structure, it can be easily formed by cutting as compared with the stopper gap 21. At the stage where the separation groove 20 is formed, the weight body 15 and the limiting member 1
It is not yet separated from 9 and remains bound by the second layer 17. Next, in the third step of FIG. 4, the joint surface 18 of the weight body 15 and the joint surface 32 of the limiting member 19 are formed on the diaphragm member 10 on which the acting portion 12, the flexible portion 13 and the fixing portion 14 are formed. It is joined by the joining method. As described in the configuration description, the weight body 15
The joining surface 18 of the diaphragm member 10 is joined to the lower surface of the acting portion 1 of the diaphragm member 10, and the joining surface 32 of the limiting member 19 is joined to the lower surface of the fixing portion 14 of the diaphragm member 10. Weight 15
Since the bonding surfaces 18 and 32 of the limiting member 19 and the diaphragm member 10 are bonded to each other by glass and silicon, they can be easily bonded by the anodic bonding method. Then, in a fourth step of FIG. 5, a stopper gap 21 is cut and formed in the second layer 17 made of silicon with a dicing saw, and the weight body 15 and the limiting member 19 are separated. Since the stopper gap 21 is formed in the second layer 17 made of silicon which is easy to cut by the dicing saw and has a small cutting resistance, it is possible to set the stopper gap 21 to about 10 μm, which is extremely small and is not possible with glass. In addition, it is possible to prevent damage during cutting, and it is possible to significantly reduce the cutting time.

In such a semiconductor acceleration sensor, when the acceleration acts, the weight body 15 suspended in the air is displaced accordingly, whereby the flexible portion 13 of the diaphragm member 10 is displaced.
And the diaphragm member 10 is displaced. By detecting the displacement of the diaphragm member 10 using the piezo effect or the like, the magnitude of the applied acceleration can be detected. According to such a configuration, the diaphragm member 10 is bonded to the weight body 15 and the limiting member 19 by silicon and glass, and the base material 30 forming the weight body 15 and the limiting member 19 is also glass. Since this is the bonding of silicon with silicon, the anodic bonding method can be used without causing any problems in bonding. Further, since the stopper gap 21 is formed in the second layer 17 made of silicon which is easy to cut by the dicing saw and has a small cutting resistance, it is possible to cut and form a stopper gap having a smaller width. In addition, the vibration transmitted to the diaphragm member 10 is small, so that it is possible not only to prevent damage during cutting, but also to significantly reduce the cutting time as compared with the case of glass. 1 mm / sec-10 m
It has been confirmed by the present inventor that cutting can be performed at a speed of m / sec.

In the above-described embodiment, the recess 17a for preventing the displacement of the weight body 15 is formed in the second layer 17 made of silicon. However, as in the conventional example of FIG. It may be formed on the upper surface of 22.

[0018]

As described above, according to the present invention, the weight body and the limiting member have a two-layer structure of a first layer made of glass and a second layer made of silicon, and are made of glass. Since the first layer is formed on the side of joining to the diaphragm member made of silicon, and the stopper gap is formed at the second layer made of silicon, the joining can be facilitated and glass is not used. It is possible to cut a stopper gap with a width that is almost impossible, greatly improving impact resistance, and preventing damage during cutting and greatly shortening the cutting time. A semiconductor acceleration sensor can be provided.

[Brief description of drawings]

FIG. 1 is a sectional configuration diagram showing an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of the semiconductor acceleration sensor having the configuration of FIG. 1, showing a first step.

FIG. 3 is a manufacturing process diagram of the semiconductor acceleration sensor having the configuration of FIG. 1, showing a second step.

FIG. 4 is a manufacturing process diagram of the semiconductor acceleration sensor having the configuration of FIG. 1, showing a third step.

FIG. 5 is a manufacturing process drawing of the semiconductor acceleration sensor having the configuration of FIG. 1, showing a fourth step.

FIG. 6 is a cross-sectional configuration diagram showing a conventional example of a semiconductor acceleration sensor.

[Explanation of symbols]

 10 diaphragm member 12 action part 13 flexible part 14 fixing part 15 weight body 16 first layer 17 second layer 18 joining surface 19 limiting member 21 stopper gap 30 base material 32 joining surface

Claims (1)

[Claims] 1. A diaphragm member made of silicon having a working portion in the central portion and a fixing portion formed around the working portion through a flexible portion, and a central portion of one surface joined to the working portion of the diaphragm member. A weight body suspended and held, a limiting member spaced apart from the outer periphery of the weight body and having one surface joined to a fixed portion of the diaphragm member, and a side portion of the weight body facing the side portion. In a semiconductor acceleration sensor having a stopper gap of a predetermined width formed between a side portion of the limiting member, a base material forming the weight body and the limiting member is made of glass and a first layer made of glass. In the two-layer structure in which the first layer is joined to the diaphragm member, the weight body and the limiting member are joined to the working portion and the fixing portion of the diaphragm member, respectively. And has, a semiconductor acceleration sensor stopper gap of the predetermined width to the second layer are formed.