JPH10239194A - Semiconductor pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor pressure sensor, of which the resistance of a piezoelectric resistor can be regulated easily. SOLUTION: A plurality of piezoelectric resistor elements 1 are formed on a diaphragm formed on a semiconductor substrate and a contact hole 2 is made at the end part of each piezoelectric resistor element 1 using photolithography process and etching process. When interconnection of a semiconductor pressure sensor is carried out by a metallization 3 of aluminum Al, or the like, the piezoelectric resistor elements 1 are connected electrically in parallel by a conductor layer, i.e., the metallization 3, through the contact holes 2. Subsequently, the metallization 3 connecting the piezoelectric resistor elements 1 in parallel is subjected to laser trimming at desired part so that the piezoelectric resistor element has a resistance bound from the rated driving voltage and current and a desired output voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor pressure sensor, and more particularly to a semiconductor pressure sensor capable of adjusting a resistance value of a piezoresistive element after a wafer process.

[0002]

2. Description of the Related Art Hitherto, formation of a piezoresistive element on a diaphragm of a semiconductor substrate having a diaphragm is performed by using a resistance value of a necessary piezoresistor obtained from a rated drive voltage, a current value and a desired output voltage value. By designing the L / W of the piezoresistive element in advance so as to determine the sheet resistance and then performing the mask design and process, as shown in FIG. 2 are electrically connected by a metal wiring 3 of aluminum (Al) or the like via the wiring 2 so as to be connected in series.

[0003]

However, the above configuration has a problem that the resistance value of the piezo resistor cannot be adjusted after the semiconductor pressure sensor is formed.

The present invention has been made in view of the above points, and an object of the present invention is to provide a semiconductor pressure sensor capable of easily adjusting the resistance value of a piezo resistor.

[0005]

According to the first aspect of the present invention,
In a semiconductor pressure sensor including a semiconductor substrate having a diaphragm, a plurality of piezoresistive elements formed on the diaphragm, and metal wiring electrically connected to the piezoresistive element, the piezoresistive element is It is characterized in that the conductor layers are connected in parallel.

According to a second aspect of the present invention, in the semiconductor pressure sensor according to the first aspect, the metal wiring is used as the conductor layer.

According to a third aspect of the present invention, in the semiconductor pressure sensor according to the first aspect, a thin film resistor is used as the conductor layer.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a formation pattern of a piezoresistive element 1 of a semiconductor pressure sensor according to one embodiment of the present invention. In the semiconductor pressure sensor according to the present embodiment, a plurality of piezoresistive elements 1 are formed on a diaphragm of a semiconductor substrate (not shown) having a diaphragm, and each piezoresistive element is formed using a photolithography process and an etching process. A contact hole 2 is formed in a terminal portion of the semiconductor pressure sensor 1 through a metal wire 3 made of aluminum (Al) or the like. And electrically connected by a metal wiring 3 as a conductor layer.

After that, the metal wiring 3 connecting the piezoresistive elements 1 in parallel with each other so that the required driving voltage and current value and the required piezoresistor resistance value obtained from the desired output voltage value is obtained. Is trimmed with a laser.

For example, when measuring the pressure at a low current, as shown in FIG. 1, the resistance value is increased by trimming the metal wiring 3 at a desired location with a laser, and the output voltage is increased. Will increase in proportion to

Therefore, in the present embodiment, in this embodiment, a plurality of piezoresistive elements 1 are connected in parallel by a metal wiring 3 through a contact hole 2, and the metal wiring 3 at a desired location is trimmed by a laser. In this way, the resistance value is adjusted, so that the resistance value of the piezo resistor can be adjusted even after the semiconductor pressure sensor is formed.

In addition, since the resistance value can be adjusted after the formation of the semiconductor pressure sensor, a sample can be manufactured promptly.

Further, in the present embodiment, since the plurality of piezoresistive elements 1 are connected in parallel by the metal wiring 3 used for the wiring of the semiconductor pressure sensor, the resistance value of the piezoresistor can be adjusted without increasing the number of steps. Becomes possible.

In this embodiment, the metal wiring 3
Is used to connect a plurality of piezoresistive elements 1 in parallel. However, the present invention is not limited to this. For example, a plurality of piezoresistive elements 1 are connected in parallel using a thin-film resistor such as low-resistance polysilicon. In this case, trimming by laser can be further easily performed.

[0015]

According to the first aspect of the present invention, there is provided a semiconductor substrate having a diaphragm, a plurality of piezoresistive elements formed on the diaphragm, and a metal wiring electrically connected to the piezoresistive element. In the semiconductor pressure sensor, the piezoresistive elements are connected in parallel by a conductor layer, so that the conductor layer at a desired location can be trimmed by a laser to increase the resistance value of the piezoresistor. A semiconductor pressure sensor whose resistance value can be easily adjusted can be provided.

According to a second aspect of the present invention, in the semiconductor pressure sensor according to the first aspect, since a metal wiring is used as the conductor layer, a plurality of piezoresistive elements are simultaneously connected to the metal wiring when wiring the semiconductor pressure sensor. Therefore, a semiconductor pressure sensor in which the resistance value of the piezoresistor can be adjusted can be formed without increasing the number of steps.

According to a third aspect of the present invention, in the semiconductor pressure sensor according to the first aspect, a thin film resistor is used as the conductor layer, so that trimming by laser can be further easily performed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a formation pattern of a piezoresistive element 1 of a semiconductor pressure sensor according to one embodiment of the present invention.

FIG. 2 is a schematic view showing a formation pattern of a piezoresistive element 1 of a semiconductor pressure sensor according to a conventional example.

[Explanation of symbols]

 1 Piezoresistive element 2 Contact hole 3 Metal wiring

Claims (3)

[Claims] A semiconductor substrate having a diaphragm, a plurality of piezoresistive elements formed on the diaphragm,
A semiconductor pressure sensor comprising: a metal wiring electrically connected to the piezoresistive element; wherein the piezoresistive element is connected in parallel by a conductor layer. 2. The semiconductor pressure sensor according to claim 1, wherein said metal wiring is used as said conductor layer. 3. The semiconductor pressure sensor according to claim 1, wherein a thin film resistor is used as said conductor layer.