JPH04238269A - Semiconductor acceleration sensor - Google Patents

Abstract

PURPOSE:To obtain the structure of a semiconductor acceleration sensor so that a weight can be stuck at the fixed position of a sensor chip and the adhesive strength can be improved by an adhesive. CONSTITUTION:A stopper section 9 is provided in the chip adhesive groove 8 of a weight 7, the stopper section 9 is stuck at the tip face 1a of a sensor chip 1, and the positioning of the weight 7 can be performed easily and correctly. An adhesive area expanding hole 10 is provided in the chip adhesive groove 8, when the weight 7 is stuck at the free end of the sensor chip 1 with an adhesive 6, the adhesive 6 infiltrates into the adhesive area expanding hole 10, the adhesive area of the adhesive 6 to the weight 7 is expanded as compared with a flat plane, and the adhesive strength between the sensor chip 1 and the weight 7 is increased that much.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a semiconductor acceleration sensor that detects acceleration using a sensor chip whose one end is fixed to a pedestal on a base and whose free end has a weight attached with an adhesive.

0002

2. Description of the Related Art FIG. 3 is a perspective view showing the structure of a conventional semiconductor acceleration sensor.

The structure of this semiconductor acceleration sensor will be explained based on FIG. 3 in accordance with the assembly order. First, one end of the sensor chip (1) that detects acceleration as strain is fixed to a prismatic pedestal (2) with adhesive, and then the pedestal (2) is fixed onto the base (3) with adhesive. . after that,
A weight (4) is attached to the free end of the sensor chip (1), and the sensor chip (1) is bonded with adhesive while the chip adhesion groove (5) provided on the bottom surface of the weight (4) is fitted into the sensor chip (1). do. An alloy-based die-bonding material is used as the adhesive for bonding these parts together.

In a semiconductor acceleration sensor having this type of structure, the sensor chip (1) is distorted by the inertial force of the weight (4) when it receives acceleration, and acceleration is detected from the distortion of the sensor chip (1).

[0005]

However, in the structure of the conventional semiconductor acceleration sensor, when attaching the weight (4) to the free end of the sensor chip (1), there is no means for positioning the sensor chip (1) in the longitudinal direction. Since there is no weight (4)
There has been a problem in that the adhesion position varies from acceleration sensor to acceleration sensor. If the adhesive position of the weight (4) varies,
The characteristics of acceleration detection also vary depending on the acceleration sensor.

Furthermore, in the conventional structure, the sensor chip (1
) and the weight (4) is insufficient because the bonding is between flat surfaces, and there is a problem in that the weight (4) may fall off due to impact during acceleration detection.

The present invention has been made to solve these problems, and provides a structure for a semiconductor acceleration sensor that can bond a weight to a fixed position on a sensor chip and increase the bonding strength. The purpose is to

[0008]

[Means for Solving the Problems] In order to achieve the above object, the semiconductor acceleration sensor of the present invention includes a stopper portion for abutting the tip end surface of the sensor chip in the chip bonding groove of the weight, and a bonding area expansion hole. and has been established.

[0009]

[Operation] The above stopper part is provided in the chip bonding groove, and when the weight is bonded to the free end of the sensor chip, the sensor chip is fitted into the chip bonding groove, and the tip surface of the sensor chip is brought into contact with the stopper part. By doing so, the weight can be positioned easily and reliably.

[0010] Furthermore, if the bonding area enlarging hole is provided in the chip bonding groove, when the weight is bonded to the free end of the sensor chip with an adhesive, the adhesive penetrates into the bonding area expanding hole and the weight is expanded. The bonding area of the adhesive to the sensor chip is larger than that in the case of a flat surface, and the bonding strength between the sensor chip and the weight increases accordingly.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional side view of a main part of a semiconductor acceleration sensor according to the present invention, and FIG. 2 is a plan view of a main part of the acceleration sensor. In FIGS. 1 and 2, components that are the same as those in the conventional example shown in FIG. 3 are denoted by the same reference numerals, and explanations thereof will be omitted.

As shown in the figure, the feature of this semiconductor acceleration sensor is that an adhesive (6) is attached to the free end of the sensor chip (1).
It is in the structure of the weight (7) that is glued.

That is, this weight (7) has the following on its lower surface:
A stopper portion (9) is provided with a chip adhesion groove (8) into which the sensor chip (1) is fitted, and in which the tip end surface (1a) of the sensor chip (1) abuts. and an adhesive area enlargement hole (10).

The stopper portion (9) is constituted by, for example, a stepped portion formed on the bottom surface of the chip bonding groove (8).

This stopper portion (9) is provided in the chip bonding groove (8), and when bonding the weight (7) to the free end of the sensor chip (1), the sensor chip (1) is placed in the chip bonding groove (8). ), and the sensor chip (1
) by bringing the tip end surface (1a) of the sensor chip (1a) into contact with the stopper part (9), the weight (7) can be easily and reliably positioned. Can be glued with high precision.

On the other hand, the bonding area expansion hole (10) is provided at the part of the chip bonding groove (8) that fits with the sensor chip (1). Consists of a drilled through hole. Further, the bonding area enlarged hole (10) is a hole where r<2h, where the radius r and the depth h are the same.

If this bonding area expansion hole (10) is provided in the chip bonding groove (8), when the weight (7) is bonded to the free end of the sensor chip (1) with the adhesive (6), the When the adhesive (6) enters the adhesive area expansion hole (10), if r<2h, the adhesive (6) is applied to the weight (7).
The bonding area of the sensor chip (1) and the weight (7) is larger than that of a flat surface, and the bonding strength between the sensor chip (1) and the weight (7) increases accordingly.

Furthermore, regarding the adhesion area of the adhesive (6), since the stopper part (9) is provided, the adhesive (6) can be bonded between the stopper part (9) and the sensor chip (1).
The weight (7) also enters between the tip surface (1a) of the
It is also expanded to the sensor chip (1). Therefore, the adhesive strength between the sensor chip (1) and the weight (7) can be further increased.

[0020] In the present invention, the adhesion area enlargement hole is a through hole, but it may also be a recess, and as in the case of a through hole, there is no recess or hole, and the adhesion area is expanded more than when it is flat. This increases adhesive strength.

[0021]

As explained above, in the semiconductor acceleration sensor of the present invention, the weight can be accurately bonded to a fixed position on the sensor chip, so that the bonding position of the weight is less likely to vary from one acceleration sensor to another.

Furthermore, since the adhesive strength between the sensor chip and the weight can be increased, there is no risk that the weight will fall off during acceleration detection.

That is, according to the present invention, it is possible to realize a highly reliable semiconductor acceleration sensor with constant acceleration detection characteristics.

[Brief explanation of the drawing]

FIG. 1 is a sectional side view of a main part of a semiconductor acceleration sensor according to an embodiment of the present invention.

FIG. 2 is a plan view of essential parts of a semiconductor acceleration sensor according to an embodiment of the present invention.

FIG. 3 is a perspective view of a conventional semiconductor acceleration sensor.

[Explanation of symbols]

(1) Sensor chip (1a) Tip surface (2) Pedestal (3) Base (6) Adhesive (7) Weight (8) Chip adhesive groove (9) Stopper part (10) Adhesive area expansion hole

Claims (1)

[Claims] Claim 1: One end of a sensor chip that detects acceleration as strain is fixed to a pedestal on a base, a weight is attached to the other free end of the sensor chip, and a chip bonding groove provided on the weight and the sensor chip. In a semiconductor acceleration sensor which is bonded with an adhesive in a state where the two are fitted together, a stopper portion for abutting the tip end surface of the sensor chip and a bonding area expansion hole are provided in the chip bonding groove of the weight. A semiconductor acceleration sensor characterized by: