JPH10177034A - Capacitance type acceleration sensor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitance type acceleration sensor that can be manufactured at a high productivity without forming its weight body by dicing and has such as electrode structure that can secure stable continuity and a highly reliable constitution, and the main body of which can be constructed thoroughly airtightly. SOLUTION: The capacitance type acceleration sensor can be manufactured with a high productivity, because its weight body 12 is not formed by dicing, which produces particles, but by the etching technique by utilizing the thickness of a substrate, at the time of providing the weight body 12 in a mobile section 11b formed by providing a supporting structure of a beam 11a. In addition, since the sensor is constituted by successively laminating and sticking substrates which are manufactured by patterning substrate in desired shapes upon another, the sensor itself can be constituted thoroughly airtightly and, since electrodes 14 and 15 are formed on the surface of a semiconductor substrate 16 provided with an external electrode 18 and exposed in a through hole formed through a glass substrate 13 stuck to the substrate 16 and the through hole by vapor deposition, the sensor has such an electrode structure that can secure stable continuity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a capacitance type acceleration sensor which can detect a static acceleration and a dynamic acceleration such as gravity in three axial directions, and to form a weight body by dicing. Without making the flexible substrate itself a weight body, and making the sensor itself completely confidential,
The present invention relates to a capacitive acceleration sensor having a highly reliable configuration and a method of manufacturing the same.

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open Nos. 4-148833 and 4-33743 disclose capacitive acceleration sensors.
No. 1, Japanese Patent Application Laid-Open No. 5-188079 discloses a method in which a plurality of capacitance elements are provided opposite to each other by attaching electrodes to opposite surfaces of a fixed substrate and a flexible substrate, and an XY plane parallel to the substrate surface is provided. And a change in acceleration in a three-dimensional direction of the X, Y, and Z axes of the Z axis orthogonal to the X axis is detected based on a change in capacitance between a plurality of capacitance elements. Has been proposed.

For example, as shown in the perspective view of FIG. 6 and the cross-sectional view of FIG. 7, the beam supporting the flexible substrate 1 is divided into four parts, excluding the central part of the rectangular flexible substrate. In the configuration example in which the substrate is arranged in a cross shape on a line, a fixed substrate 3 arranged in parallel with the flexible substrate 1 at a predetermined interval via the pedestal glass 2 and an upper glass substrate 4 are arranged, and opposing electrodes X ₁ , X ₂ ,
Capacitance elements C _{1 to} C ₄ are formed by attaching Y ₃ and Y ₄ , and a glass weight 5 having an appropriate mass is provided on the divided lower surface of the flexible substrate 1. is there.

The upper glass 4 disposed on each of the opposing surfaces of the flexible substrate 1 leads to the outside from the electrode on the opposing surface.
The flexible substrate 1 is cut through a notch gap provided around the upper glass 4.
An electrode take-out pad 6 is provided on the upper side so that a lead 7 can be connected.

In general, a capacitance type acceleration sensor is
In order to reduce the influence of the atmosphere during use and to prevent foreign matter from entering the capacitance gap, it is relatively expensive, but is used as a sensor chip with a hermetic seal package and controlled gas inside. Was.

[0006]

However, the capacitance type acceleration sensor having the above-mentioned conventional configuration is not suitable for the flexible substrate 1.
When the glass weight body 5 is provided on the divided lower surface of, the glass is formed by dicing, and as shown in FIG.
Since dicing grooves are formed on the side surfaces, it is difficult to keep secrets.Particles may enter the capacitance gap during dicing, leading to a reduction in yield. Since there is a gap due to the notch provided around the glass 4, there is a problem that reliability is lacking because particles in the package may enter the capacitance gap.

FIGS. 8 and 9 show a method for conducting a lead from an electrode facing a flexible substrate without exposing the electrode. In the case of FIG. 8, the movable portion 1a may be provided on the fixed substrate 3. A flexible substrate 1 is provided, and a glass substrate 4 on which electrodes are further provided is laminated and arranged. A through hole having a tapered surface is provided in the glass substrate 4, and a predetermined counter electrode is formed on both surfaces sandwiching the through hole by vapor deposition. By forming 4a and 4b,
The opposing electrodes 4a and 4b opposing the movable portion 1a are exposed on the upper surface through the through-holes, and the conductor cap 8 laminated thereon is provided with a lead portion 9 made of solder or the like. However, the electrode configuration of vapor deposition on both sides through this through hole, the thickness of the deposited film tends to be uneven because the hole end is bent at an acute angle, there is a concern that poor conduction and the like,
Further, there is a problem that the number of electrodes that can be taken out is limited to one.

Further, in the case of the configuration shown in FIG.
A flexible substrate 1 having a movable portion 1a is provided thereon, and a glass substrate 4 further provided with electrodes 4a and 4b is laminated and arranged.
The electrodes 4a and 4b are arranged at the positions of the through holes having a tapered surface provided on the glass substrate 4, and the lead portions 9 made of a conductive paste or the like are provided in the through holes from outside. However, in mass production, there is a problem that the cost is increased due to the application of the conductive paste and the routing of the lead wires.

SUMMARY OF THE INVENTION The present invention solves the problems of the conventional capacitance type acceleration sensor having a reduced yield and lack of reliability, can be manufactured with high productivity without forming a weight body by dicing, and can manufacture the sensor itself. Provided is a capacitive acceleration sensor having a highly reliable configuration having a plurality of electrode structures capable of ensuring stable conduction without using an expensive hermetic package, which can be completely airtight, and a method of manufacturing the same. And

[0010]

SUMMARY OF THE INVENTION The inventor of the present invention has proposed a configuration in which a weight provided on the lower surface of a movable portion of a flexible substrate can be manufactured with high productivity without forming by dicing, and the sensor itself can be completely confidential. As a result of various investigations, we focused on the fact that the silicon substrate itself as a flexible substrate was integrally formed with a weight body by photolithography etching and the substrates were laminated and integrated and hermetically sealed. As a configuration that is connected to the silicon substrate provided on the opposite surface by the provided through hole, it was found that there is no need to form a gap where the external atmosphere enters the weight body part and the lead part of the electrode at the time of manufacturing. Thus, the present invention has been completed.

That is, according to the present invention, a weight is provided on the lower surface of a plurality of movable portions of a flexible substrate having a support structure by a beam, and a fixed substrate is disposed opposite to the fixed substrate. In a capacitance type acceleration sensor provided with a capacitance gap portion, a flexible substrate having a weight body with a relatively thick movable portion formed by providing a supporting structure by patterning on a semiconductor substrate is provided on a fixed substrate. The electrodes provided in a required pattern on both surfaces of a composite board in which a glass substrate having a conical or pyramid-shaped through-hole provided in a required pattern and a semiconductor substrate are joined on the conical top side of the through-hole are connected to each other through the through-hole. Wherein a composite plate having a configuration in which the electrodes are electrically connected to each other via a semiconductor is joined to the upper surface of the flexible substrate by arranging electrodes facing each other, and the inside is hermetically sealed.

Further, the present invention provides a method for joining a semiconductor substrate and a glass substrate having a conical or pyramid-shaped through hole provided in a required pattern on the conical top side of the through hole, and forming a required part on both surfaces of the obtained composite plate. The electrodes provided in a pattern form a glass composite plate having a configuration in which the electrodes are electrically connected to each other through the semiconductor substrate in the through holes.
On the other hand, the semiconductor substrate is provided with a beam-supporting structure by a dry or wet etching technique to form a flexible substrate having a relatively thick movable portion formed by attaching a weight to the movable portion. The glass composite plate is laminated and bonded, and bonded and integrated on a fixed substrate in a required atmosphere, and thereafter, an electrical insulating groove is provided in a required pattern on the uppermost electrode layer and the semiconductor substrate, and further, on a required chip. This is a method for manufacturing a capacitance type acceleration sensor characterized by cutting and separating.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a capacitive acceleration sensor according to the present invention and a method for manufacturing the same will be described in detail. 1 is a longitudinal sectional view of a capacitance type acceleration sensor according to the present invention, FIG. 2 is a longitudinal sectional view showing another configuration, FIGS. 3A to 3D are longitudinal sectional views showing an assembling sequence of a glass composite plate, and FIG. FIG. 5 is a vertical sectional view of the flexible substrate, and FIG. 5 is a vertical sectional view of the fixed substrate.

The capacitance type acceleration sensor according to the present invention shown in FIG. 1 has a flexible substrate 11 provided with a weight 12 formed on a fixed substrate 10 using the thickness of the substrate, and opposing electrodes 14 and 1.
5 and a glass composite plate 17 comprising a semiconductor substrate 16 are sequentially laminated.

An example of the manufacturing method will be described. As shown in FIG. 3B, a glass substrate 13 and a semiconductor substrate 16 having a conical or pyramid-shaped through hole provided in a required pattern by sandblasting or the like are formed as shown in FIG. Anode bonding is performed on the conical top side of the through hole, and then external electrodes 18 are provided on the entire upper surface of the semiconductor substrate 16 and required pattern electrodes 14 and 15 are provided on the glass substrate 13 as shown in D.

An external electrode 18 can be provided on the entire upper surface of a semiconductor substrate 16 such as a low-resistance doped silicon substrate by forming a metal such as Al, Au, or Cu, by vapor deposition or plating. 13 can be formed by a technique such as vapor deposition patterning using a metal mask or the like.

As shown in FIG. 4, a movable portion 11 formed separately by providing a support structure with a beam 11a on a semiconductor substrate such as a silicon substrate by a dry or wet etching technique.
The flexible substrate 11 provided with the weight body 12 by relatively increasing the thickness b is manufactured.

The above-mentioned glass composite plate 17 is placed on the flexible substrate 11.
Are laminated so as to face each other, and anodically bonded. As shown in FIG. 5, the flexible substrate 11 is laminated on the fixed substrate 10 on which a so-called counterbore is formed, and anodically bonded. At this time, the atmosphere in the laminated body is controlled by adjusting the atmosphere during the bonding. Can be kept.

At a depth corresponding to the thickness of the electrode 18 and the semiconductor substrate 16 on the upper surface of the integrated laminate, insulating grooves are formed in a required pattern as shown in FIG. The portion of the semiconductor substrate 16 connected to the electrodes 14 and 15 is electrically separated, and conduction from the external electrodes 18 on the upper surface provided on the separated semiconductor substrate 16 to the opposing electrodes 14 and 15 is ensured.

Although the configuration shown in the figure shows one sensor, a large number of patterns are formed on a glass substrate or a semiconductor substrate of a required size during manufacture, and a required chip after assembly and integration, that is, the chip shown in FIG. By cutting and separating into two, a capacitive acceleration sensor can be obtained.

In the present invention, the flexible substrate 11 in the capacitance type acceleration sensor can be manufactured from one semiconductor substrate as shown in FIG. Further, as shown in FIG. 2, when a support structure using a beam 11a is provided by an etching technique from a substrate obtained by bonding two semiconductor substrates, the weight of one substrate can be used as the weight body 12. It is.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In manufacturing a capacitance type acceleration sensor having the structure shown in FIG. 1, a weight body 12 is attached to a fixed substrate 10 having a concave portion formed by photolithography on Pyrex glass by utilizing the thickness of the substrate. Flexible substrate 11
And a semiconductor substrate 16 on which an aluminum electrode constituting an external electrode is vapor-deposited on the upper surface, and the opposite electrodes 14, 1 by anodic bonding.
The glass substrate 13 provided with No. 5 was manufactured by the manufacturing method of the present invention using the anodic bonding technology. In addition,
The atmosphere during the integral joining was an inert gas.

A large number of capacitive acceleration sensors having a substrate size of 4 inches have a relatively improved yield as compared with the conventional one shown in FIG. However, in a high-temperature and high-humidity atmosphere and a low-temperature condition use test, performance equivalent to a hermetic seal product was obtained.

[0024]

According to the present invention, when the weight is provided on the movable portion formed by providing the beam supporting structure, which is the most important portion of the capacitive acceleration sensor, the weight is formed by dicing in which particles are generated. Without using the etching technology, the weight body is formed using the thickness of the substrate, so that it can be manufactured with high productivity. The substrate itself is sequentially laminated and joined by the required patterning, so that the sensor itself is completely airtight. In addition, since the electrodes are formed by vapor deposition on the semiconductor substrate surface exposed in the through holes provided in the glass substrate bonded to the semiconductor substrate provided with the external electrodes and the through holes, stable conduction can be ensured. The capacitance type acceleration sensor according to the present invention can solve the problems of the sensor having the conventional structure, such as a decrease in manufacturing yield and a lack of reliability.

[Brief description of the drawings]

FIG. 1 is an explanatory longitudinal sectional view of a capacitance type acceleration sensor according to the present invention.

FIG. 2 is a longitudinal sectional view showing another configuration of the capacitance type acceleration sensor according to the present invention.

FIGS. 3A to 3D are longitudinal sectional views showing an assembling sequence of the glass composite plate according to the present invention.

FIG. 4 is an explanatory longitudinal sectional view of a flexible substrate according to the present invention.

FIG. 5 is an explanatory longitudinal sectional view of a fixed substrate according to the present invention.

FIG. 6 is an explanatory perspective view of a conventional capacitance type acceleration sensor.

FIG. 7 is an explanatory longitudinal sectional view of the capacitance type acceleration sensor of FIG. 6;

FIG. 8 is an explanatory longitudinal sectional view of another conventional capacitance type acceleration sensor.

FIG. 9 is an explanatory longitudinal sectional view of another conventional capacitive acceleration sensor.

[Explanation of symbols]

1 the flexible substrate 1a movable portion 2 pedestal glass 3 fixed substrate 4 a glass substrate 4a, pad 7 leads 8 conductor cap 9 leads X ₁ extraction 4b counter electrode 5 glass weight body 6 _{electrodes, X 2, Y 3, Y} 4 facing Electrode 10 Fixed substrate 11 Flexible substrate 11a Beam 11b Movable part 12 Weight 13 Glass substrate 14, 15 Counter electrode 16 Semiconductor substrate 17 Glass composite plate 18 External electrode

Claims (2)

[Claims] 1. A flexible substrate having a support structure by a beam, a weight body is provided on the lower surface of a plurality of movable parts, a fixed substrate is arranged opposite thereto, and an electrode is arranged opposite to an upper surface of the movable part to form a capacitance gap portion. In the capacitance type acceleration sensor provided with, a flexible substrate having a weight body with a relatively thick movable portion formed by providing a support structure by patterning on a semiconductor substrate is joined to a fixed substrate, The electrodes provided in a required pattern on both sides of a composite board in which a glass substrate having a conical or pyramid-shaped through hole provided in a required pattern and a semiconductor substrate are joined on the conical top side of the through hole are connected to each other through a semiconductor in the through hole. A capacitive acceleration sensor in which a composite plate having a conductive configuration is joined to the upper surface of the flexible substrate by arranging electrodes facing each other and hermetically sealed. 2. A semiconductor substrate and a glass substrate having a conical or pyramid-shaped through hole provided in a required pattern are joined at the conical top side of the through hole, and provided on both surfaces of the obtained composite plate in a required pattern. The thickness of the movable part formed by providing a support structure with a beam by a dry or wet etching technique on a semiconductor substrate is made relative to a glass composite plate in which electrodes are electrically connected to each other via a semiconductor in the through hole. A flexible substrate with a weight body attached thereto, and a glass composite plate laminated and joined on the flexible substrate, which is joined and integrated on a fixed substrate in a required atmosphere, and then the uppermost surface A method for manufacturing a capacitive acceleration sensor in which an insulating groove is provided in a required pattern on an electrode layer and a semiconductor substrate, and further cut and separated into required chips.