JPH0465644A - pressure sensor - Google Patents

Abstract

PURPOSE:To eliminate contact parts between strain gauges and aluminum electric conductors on a diaphragm area and to reduce noises by providing diffused wiring layers which connect the strain gauges. CONSTITUTION:When stress is applied to the diaphragm area 2, gauge resistances 3 vary in resistance values and output voltages corresponding to their resistance values. The diffused wiring layers 5 connect the gauge resistances 3 and the contact parts for the aluminum electric conductors 4 are not present in the diaphragm area 2. Consequently, when the stress is applied to the diaphragm area 2, the contact parts between the gauge resistances 3 and aluminum electric conductors 4 are never strained unlike before and noises are reduced. Further, there are four contact parts between the diffused wiring layers 5 and aluminum electric conductors 4 and the contact parts themselves are reduced to half, so noises are further reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to pressure sensors, and more particularly to connections between a plurality of strain gauges formed on a diaphragm region provided on a substrate.

[Conventional technology]

FIG. 2 is a top view of a conventional pressure sensor chip with a diaphragm region. A gauge resistor 3 is formed at the center of each side of a square diaphragm region 2 formed on a semiconductor substrate 1. Gauge resistor 3 is formed of an impurity diffusion layer.

Both ends of the gauge resistors 3 are connected to each other by aluminum wiring 4, and a bridge circuit is formed by the four gauge resistors 3.

Next, the operation will be explained. When stress is applied to the diaphragm region 2, the resistance value of the gauge resistor 3 changes depending on the magnitude of the stress, and a voltage corresponding to this resistance value is output.

[Problem to be solved by the invention]

The conventional pressure sensor is constructed as described above, and there are eight contact parts between the gauge resistor 3 and the aluminum wiring 4 on the diaphragm region 2 which is subjected to stress, and the stress tends to cause distortion in the contact parts and generate noise. . Another problem is that the contact portion itself tends to cause noise.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain a pressure sensor that is less likely to generate noise.

[Means to solve the problem]

A pressure sensor according to the present invention includes a semiconductor substrate, a diaphragm region formed on the semiconductor substrate, and a plurality of strain gauges formed on the diaphragm region and converting stress applied to the diaphragm region into electrical signals. , a diffusion wiring layer formed on the semiconductor substrate for connecting the plurality of strain cages.

[Effect]

In this invention, since the plurality of strain gauges formed on the diaphragm region are connected by the diffusion wiring layer, it is possible to eliminate the contact portion between the strain gauges and the aluminum wiring on the diaphragm region.

〔Example〕

FIG. 1 is a top view showing an embodiment of a pressure sensor according to the present invention. In the figure, the difference from the conventional example shown in FIG. I made contact with them. Diffusion wiring layer 5 is formed by diffusing impurities into semiconductor substrate 1 so as to be adjacent to cage resistor 3 . The aluminum wiring 4 connects the pressure sensor to the power supply voltage ■. It provides C or GND potential and serves as an output drawer.

The operation is the same as before. That is, when stress is applied to the diaphragm region 2, the resistance value of the cage resistor 3 changes, and a voltage corresponding to this resistance value is output. Connections between the plurality of gauge resistors 3 are made by a diffusion wiring layer 5, and there is no contact portion with the aluminum wiring 4 on the diaphragm region 2.

Therefore, when stress is applied to the diaphragm region 2, distortion does not occur in the contact portion between the gauge resistor 3 and the aluminum wiring 4 as in the conventional case, and noise is reduced. Further, the number of contact portions between the diffusion wiring layer 5 and the aluminum wiring 4 is four as shown in the figure, and the number of contact portions themselves is reduced by half or half, further reducing noise.

In the above embodiment, a strain gauge was used as a strain gauge to convert the stress applied to the diaphragm region 2 into an electrical signal, but other gauges may be used.

〔Effect of the invention〕

As described above, according to the present invention, after providing a diffusion wiring layer for connecting a plurality of strain gauges formed on a diaphragm region, a contact portion between a strain cage and an aluminum wiring is provided on a diaphragm region. It is possible to eliminate it. As a result, no stress is applied to the contact portion, which has the effect of reducing noise.

[Brief explanation of drawings]

FIG. 1 is a top view showing an embodiment of a pressure sensor according to the present invention, and FIG. 2 is a top view of a conventional pressure sensor. In the figure, 1 is a semiconductor substrate, 2 is a diaphragm region,
3 is a gauge resistor, and 5 is a diffusion wiring layer. Note that the same reference numerals in each figure indicate the same or corresponding parts. Part 1 Figure 2

Claims (1)

[Claims] (1) A semiconductor substrate, a diaphragm region formed on the semiconductor substrate, a plurality of strain gauges formed on the diaphragm region and converting stress applied to the diaphragm region into electrical signals, and on the semiconductor substrate. A pressure sensor comprising a diffusion wiring layer for connecting the plurality of strain gauges.