JPH0728060B2 - Magnetic resistance element - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an internal wiring structure of a magnetoresistive element used in a magnetic rotation sensor or the like.

[Background of the Invention]

Conventionally, as a ferromagnetic thin film resistance element, a magnetoresistive element that constitutes a magnetic field detection unit using permalloy or the like is known (see Japanese Patent Application Laid-Open No. 57-131642).

However, along with the high integration of the magnetic field detection unit, it is necessary to make the internal wiring between the magnetic field detection unit and the external connection terminal unit have a multilayer wiring structure.

FIG. 1 is a plan view showing an example of a magnetoresistive element having two sets of bridge circuits as a magnetic field detecting section. In the figure, the magnetic field detection unit 1 is composed of eight permalloy thin film resistors (hereinafter referred to as resistors) 1a, 1b, 1c, 1d, 1e, 1f, 1g and 1h, which are arranged with a predetermined narrow pitch. Further, at both ends of the magnetic field detecting section 1, first layer wirings 3 made of a conductive material having a resistance value sufficiently lower than the resistance value of the magnetic field detecting section 1 are formed for connecting to the external connection terminal section 2. ing.

In recent years, along with the miniaturization and high integration of the area of the magnetoresistive element, a multilayer wiring structure has been adopted to reduce the area required for wiring. In this case, an interlayer insulating film (not shown) is formed on the upper layer of the first-layer wiring 3, the second-layer wiring 4 is formed thereon, and the connection with the first-layer wiring 3 is performed only through the through-holes. The structure is used.

FIG. 2 shows an electric circuit diagram of FIG. 1 when the through holes 5 shown in FIG. 1 are arranged. In the figure, one set consists of four resistors 1a, 1b, 1e, 1f, and resistors 1c, 1d, 1g,
One set of bridge circuits is composed of four 1h. At this time, the external connection terminals (hereinafter referred to as terminals) 2b, 2
d and terminals 2c and 2e are output terminals in each bridge circuit.

However, in such a circuit configuration, the position of the through hole 5 in each bridge circuit is the terminal 2 in the terminals 2b and 2c.
It is arranged on the f side, and on the terminals 2d and 2e side, on the terminal 2a side. In this case, as apparent from FIG. 1, the connection resistance between the first layer wiring 3 and the second layer wiring 4 of the through hole 5 is
Although smaller than the resistance value of the magnetic field detection unit 1, the first layer wiring 3,
It has a larger value than the resistance of the second layer wiring 4 portion, and is also affected by variations in the manufacturing process. Therefore, when the terminals 2a and 2f are connected to a power source and the magnetic field is not applied to the magnetic field detection unit 1, the difference between the potential of the terminal 2b and the potential of the terminal 2d, the difference between the potential of the terminal 2c and the potential of the terminal 2e, That is, there is a problem that the offset voltage becomes large and the fluctuation becomes large.

[Object of the Invention]

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide an internal wiring structure of a magnetoresistive element having a small offset voltage value and little fluctuation. .

[Outline of Invention]

In order to achieve such an object, according to the present invention, the arrangement of through holes in the bridge circuit is limited to only one power supply terminal side, and the offset voltage due to the connection resistance of the first layer wiring and the second layer wiring through the through holes. It has reduced the effect on.

Example of Invention

 Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a plan view showing an example of the internal wiring structure of the magnetoresistive element according to the present invention, and the same parts as those in the above-mentioned figures are designated by the same reference numerals. In the figure, the resistors 1a, 1b, 1c, 1d, 1e, 1f, 1g and 1h which constitute the magnetic field detection unit 1 are formed and arranged in narrow pitches of about 100 μm. Then, of these resistors 1a to 1h, the resistors 1a, 1e, 1d, 1h and the terminals 2b, 2c, 2d, 2e
The first layer wiring 3 ′ made of a conductive material having a resistance value sufficiently smaller than the resistance value of the magnetic field detection unit 1 is directly connected between and. The remaining resistors 1c, 1g, 1b, 1f are wired up to the portion where the through hole 5 can be formed in the first layer wiring 3.
An interlayer insulating film (not shown) is formed on the first layer wirings 3 and 3'except for the through holes 5 and is made of a conductive material having a small wiring resistance like the first layer wirings 3 and 3 '. The second layer wiring 4 is formed, and the first layer wirings 3 and 3'are connected to the through holes 5 to form two sets of bridge circuits.

FIG. 4 is an electric circuit diagram of the two sets of bridge circuits shown in FIG. In FIG. 4, the through-holes 5 are arranged on the power supply terminal 2f side with respect to the terminals 2b and 2c in the bridge circuit composed of the resistances 1a, 1b, 1e and 1f, and the resistance 1c,
In the bridge circuit composed of 1d, 1g, and 1h, the power supply terminal 2a side is configured with respect to 2e and 2d, respectively.

According to such a configuration, the through holes 5 are arranged in the bridging circuit in an internal wiring structure that can be uniformly arranged on one of the power supply connection terminals 2a or 2f. As a result, the first layer wiring 3 in the through hole 5,
Even if the connection resistance between 3'and the second layer wiring 4 fluctuates in the manufacturing process, each potential difference between the terminals 2b and 2c and between the terminals 2e and 2d in the absence of a magnetic field, That is, the influence on the offset voltage can be reduced.

〔The invention's effect〕

As described above, according to the present invention, it is possible to suppress the influence of the connection resistance between the respective layer wirings in the multilayer wiring structure, so that a magnetoresistive element having a small offset voltage value and a small fluctuation can be obtained, which is extremely excellent. Produce an effect.

[Brief description of drawings]

FIG. 1 is a plan view showing an internal wiring structure of a conventional magnetoresistive element having a multilayer wiring structure, FIG. 2 is an electric circuit diagram of FIG. 1, and FIG. 3 is an internal wiring structure of a magnetoresistive element according to the present invention. FIG. 4 is an electric circuit diagram of FIG. 3 showing an example of a plan view. 1 ... Magnetic field detector, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h ... Permalloy thin film resistor (resistor), 2 ... External connection terminal, 2a, 2
f …… Power supply connection terminal, 2b, 2c, 2d, 2e, 2g, 2h …… External connection terminal (terminal), 3,3 ′ …… First layer wiring, 4 …… Second layer wiring, 5 …… Through hole.

Claims (1)

[Claims] 1. A first layer wiring which is directly connected to a magnetic field detecting section (1) composed of a thin film resistor, an interlayer insulating film which is formed on the first layer wiring, and which is formed on the interlayer insulating film. In a magnetoresistive element having a second layer wiring and a through hole connecting the first layer wiring and the second layer wiring, four thin film resistors (1
The bridge circuit formed by a, 1f, 1e, 1b) has two power supply terminals (2a, 2f) for supplying an electric current, and two thin film resistors (1a, 1f) that form the bridge circuit. Between two)
The other two thin film resistors (2a) and the through hole (5) for detecting the mutual change of the resistance values of the thin film resistors (1a, 1f) and the other two thin film resistors (, An output terminal (2c) and the through hole (5) for detecting the mutual change of the resistance values of the two thin film resistors (1e, 1b) are present between 1e, 1b), and the through hole (5 ) Is a bridge circuit, which is integrally arranged on either side of the power supply terminal (2a) or the power supply terminal (2f) when viewed from the output terminals (2b, 2c) in the bridge circuit. A magnetoresistive element having.