JPS61144576A - Semiconductor acceleration sensor - Google Patents

Abstract

PURPOSE:To simplify production processes, to eliminate the temp. variation and distortion due to piezoresistance and to prevent the resistance variation of the piezoresistance by forming the lower part stopper of the cantilever of semiconductor on the substrate to package semiconductor tip and by forming the upper part stopper separate from aluminum bonding pad. CONSTITUTION:A recessed part 15b is formed on HIC substrate 23 and made as the lower part stopper for semiconductor cantilever 7 and semiconductor weight 5, also the upper part stopper 13b is formed in channel shape on the outer peripheral part of the gap 3 of the above of a silicon tip 1. The number of components can therefore be reduced without the necessity to form the stop per 15b as simple substance due to the recessed part of the substrate 23 being used as the lower part stopper 15 of the weight 5. The output errors and temp. variation of the case of using a piezoresistance 9 as bridge can be reduced because of there being no necessity of performing the electrical connection of the resistance 9 and outer part with using high density diffusion zone as well. Further due to the stopper 13b being formed on the outer peripheral part of the gap of the tip 1 the effect due to heat is relieved and the resistance variation of the resistance 9 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor acceleration sensor that has a semiconductor cantilever and measures acceleration using a piezo effect.

[Prior Art] A conventional semiconductor acceleration sensor is shown in FIG. 2, for example. This is from the literature rL,M.

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ED-26, No, 12. PP, 191 1-19
17.1979J, a detailed explanation will be given below based on FIG. 2.

Figure 2(a) is a plan view of the semiconductor acceleration sensor, and Figure 2(b) is a plan view of the semiconductor acceleration sensor.
) is a side view, and as shown in the figure, a void 3 is formed on a semiconductor chip (hereinafter referred to as a silicone chip) 1, so that a semiconductor weight (hereinafter referred to as a silicone weight) 5 is provided at the end. A semiconductor cantilever (hereinafter referred to as a silicon cantilever) 7 is formed on the silicon chip 1. A piezoresistor 9 is formed on the surface of the silicon cantilever 7 by impurity diffusion, and a high a degree diffusion region 11 is formed on the silicon chip 1 adjacent to the piezoresistor 9.

In order to prevent excessive deformation of the silicon cantilever beam 7 when excessive acceleration is applied, an upper stopper 13 and a lower stopper 15 are provided in steps C above and below the silicon chip 1, respectively. The upper stopper 13 and the lower stopper 15 each have a recess 13 so that the silicon cantilever beam 7 can be deformed.
'a, 15a is formed.

One aluminum bonding pad is formed on the lower surface of the upper stopper 13 adjacent to the high concentration diffusion region 11,
A lead wire 2 is attached to the aluminum bonding pad 19.
1 is connected.

The C acceleration is measured using such a semiconductor acceleration II sensor as follows. That is, it receives acceleration ()
The 9912 cantilever beam 7 is deflected, thereby changing the resistance value of the rainbow resistor 9 formed on the surface of the silicon cantilever beam 7. The piezoresistor 9 is a high concentration diffusion 1bX11,
It is electrically connected to the outside via an aluminum bonding pad 19 and a lead PJ 21, and the acceleration is measured by changing the resistance value of the piezoresistor 9 and changing the output voltage.

[Problems to be Solved by the Invention] However, semiconductor acceleration sensors using piezoresistance effects generally have low sensitivity, and the sensitivity is highly dependent on temperature resistance, so it is difficult to connect external amplifier circuits and temperature compensation circuits. It requires a number of circuits. In order to improve reliability and reduce cost, it is necessary to integrally form such external circuits.

However, since adjustment resistors and the like are also required, they are usually mounted on the HIC substrate 23 on which thick film resistors can be formed.

However, when mounting a semiconductor acceleration sensor on such an HIC board 23, there are problems as shown below.

■ After bonding one side of the lower stopper 15 to the silicon chip 1, the other side of the lower stopper is attached to the HIC substrate 23.
It requires many work steps.

■ When wiring the semiconductor acceleration sensor with the HIG board 23, the number of terminals for power supply, output adjustment resistance, etc. increases, and the second
In the configuration shown in the figure, it is difficult to use bonding wires.

(2) A high concentration diffusion region bA11 is formed, and when the piezoresistor 9 is used as a bridge, errors are likely to occur due to temperature changes and distortion.

(2) Thermal strain between the upper stopper 13 and the piezoresistor 9 tends to change its resistance.

[Means for Solving the Problems] The present invention was made by focusing on the problems of the conventional art, and includes forming a lower stopper of a semiconductor cantilever on a substrate on which a semiconductor chip is mounted, and an aluminum bonding pad. The above problem is solved by forming the upper stopper apart from the upper stopper.

[Example] The present invention will be explained below based on the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG.
) and (b) are a plan view and a side view of a semiconductor acceleration sensor, respectively. In the same figure, elements that perform the same functions as those of the conventional semiconductor acceleration sensor shown in FIG. 2 are given the same numbers.

In this embodiment, the lower stopper 15 of the conventional semiconductor acceleration sensor shown in FIG. Along with the lower stopper of the silicone dust 5, the collar 13b of the upper part 1 is not supported on the side of the aluminum bonding pad 19 on the silicon chip 1, but is attached to the outer periphery of the gap 3 formed on the silicon chip 1. It is formed into a U-shape.

The silicon chip 1 can be attached to the HIC substrate 23 by gold (Au) die bonding, soldering, embossment, or the like.

In this embodiment, a piezoresistor 9 is connected to an iJA integrated circuit 25 formed on a silicon chip 1, and an aluminum bonding pad 1 is placed around the integrated circuit 25.
9 is freely provided, and the bonding pad 27 provided on the HIC board 23 and the aluminum bolanding pad 19 are connected to the bonding wire 2.
Connected by 9. The integrated circuit 25 has functions such as amplification and temperature compensation, and is made of silicon chip 1.
is formed. .

With the above configuration, since the concave portion of the H[C substrate is used as the lower stopper of the silicon weight, there is no need to form the lower stopper as a single unit, and the number of parts can be reduced as well as the number of times it can be removed.

Furthermore, by making the thickness of the silicon weight 5 thinner than the thickness of the attachment portion of the silicon chip 1 to the RC substrate 23, it is not necessary to provide the recess 15b in the HIG substrate 23.

In addition, since the upper stopper is not formed on the aluminum bonding bat, the aluminum bonding bat can be easily connected with a bonding wire, which facilitates wiring and also simplifies the wiring process.

Furthermore, since there is no need to make external electrical connections to the piezoresistor using a heavily doped diffusion region, output errors and temperature changes when using the piezoresistor as a bridge can be reduced.

Furthermore, since the support part for the upper stopper is formed on the outer periphery of the silicon chip, even if the upper stopper is subjected to strain due to heat, etc., the effect of the strain on the silicon cantilever beam can be alleviated, and the piezoresistor can prevent resistance changes.

[Effects of the Invention] According to the invention described above, the manufacturing process is simplified, bonding wires can be used freely, temperature changes and distortions caused by piezoresistors are small, and resistance changes of piezoresistors are avoided. It is possible to provide a semiconductor acceleration sensor without

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are a plan view and a side view of a semiconductor acceleration sensor according to this embodiment, and FIGS. 2(a) and (b) are a front view and a side view of a conventional semiconductor acceleration sensor. . 1... Semiconductor chip 7... Semiconductor single-sided beam 9
...Piezo resistor 13a...Upper stopper 15
b... Lower stopper (recess) 19... Aluminum bonding butt 23...
HIC board 25...Integrated circuit Figure 1 (a) Figure 1 (b) 1 5 15b Figure 2 (Q) Figure 2 (b) 1'5 1 5 15Q procedural amendment type (method) Commissioner of the Patent Office Manabu Shiga 1, Indication of the incident Patent application Sho 59-26518 April 2
, Title of the invention Semiconductor Acceleration Census 3, Relationship to the person making the amendment Patent applicant address (residence) 2 Yotakaramachi, Kanagawa, MS Hama-shi Name (name) (399) Nissan Motor Co., Ltd. Representative Ishi
Shun Hara 4, Agent address: 1-2-3 Toranomon, Minato-ku, Tokyo 105
No. Toranomon No. 5, Building 5th Floor 6, Subject of amendment: ``Mei M Book'' 7. Contents of amendment (1) On page 11, line 17 of the specification, ``This is Document rL, M, J. References L., M., Laurence and G.I.
What, Angel's RL Kutsuchi type silicon acceleration sensor +
JIJEEEEAlj, Electron Device, 197
9, Vol. εD, Vol. 26, No. 12, pp. 1911-1917 rL, M, J.

Claims (1)

[Claims] A semiconductor acceleration sensor characterized in that a lower stopper of a semiconductor cantilever is formed on a substrate on which a semiconductor chip is mounted, and an upper stopper is formed on the upper part of the semiconductor cantilever apart from an aluminum bonding pad.