Magnetic sensor and manufacturing method therefor
A magnetic sensor for detecting the intensity of a magnetic field in three axial directions, in which a plurality of giant magnetoresistive elements are formed on a single semiconductor substrate. A thick film is formed on the semiconductor substrate; giant magnetoresistive elements forming X-axis and Y-axis sensors are formed on a planar surface thereof; and giant magnetoresistive elements forming a Z-axis sensor are formed using slopes of channels in the thick film. Each of the slopes of the channels can be constituted of a first slope and a second slope, so that a magneto-sensitive element is formed on the second slope having a larger inclination angle. In order to optimize the slope shape and inclination with respect to each channel, it is possible to form a dummy slope that does not directly relate to the formation of the giant magnetoresistive elements.
1. A manufacturing method for a magnetic sensor comprising:
forming a planation layer that provides planation by covering a wiring layer of a semiconductor substrate;
forming a passivation film on the planation layer;
forming a thick film on the passivation film;
forming a resist film on the thick film;
partially removing the resist film;
performing etching on the resist film and the thick film, thus forming a plurality of channels in the thick film;
forming an opening in the thick film to form a via;
forming a wiring film on a planar surface of the thick film as well as slopes, top portions, and bottom portions of the channels;
connecting the wiring film to a conductive portion of the via;
forming magneto-sensitive elements on the slopes of the channels; and
connecting the wiring film to the magneto-sensitive elements.
2. The manufacturing method for a magnetic sensor according to claim 1 , wherein the magnetic sensor is composed of a giant magnetoresistive element.
3. The manufacturing method for a magnetic sensor according to claim 1 , further comprising performing heat treatment on the resist film, thus making terminal surfaces thereof incline.
4. The manufacturing method for a magnetic sensor according to claim 1 , wherein the etching is performed to reduce the resist film and the thick film at an etching selection ratio of 1:1.
5. The manufacturing method for a magnetic sensor according to claim 1 , further comprising forming an insulating film between the thick film and the passivation film, wherein the insulating film acts as an etching stopper during the etching.
6. The manufacturing method for a magnetic sensor according to claim 1 , further comprising forming a protection film after completion of the magnetic sensor.
7. The manufacturing method for a magnetic sensor according to claim 6 , further comprising forming a conductive pad on the semiconductor substrate and exposing the conductive pad after formation of the protection film.
8. The manufacturing method for a magnetic sensor according to claim 1 , wherein each of the slopes of the channels formed by the etching is constituted of a first slope on an upper side and a second slope on a lower side, and wherein an inclination angle of the second slope is larger than an inclination angle of the first slope, and wherein the magneto-sensitive element is formed on the second slope.
9. A manufacturing method for a magnetic sensor comprising:
forming a conductive pad on a semiconductor substrate;
forming a thick film;
forming a resist film on the thick film;
performing etching on the resist film and the thick film, thus forming a plurality of channels in the thick film, each of the channels having slopes, top portions, and bottom portions;
forming an opening in the thick film to form a via exposing the conductive pad;
forming a wiring film on a planar surface of the thick film as well as the slopes, top portions, and bottom portions of the channels;
connecting the wiring film to the conductive pad;
forming magneto-sensitive elements on the slopes of the channels; and
connecting the wiring film to the magneto-sensitive elements.