JP5879025B2 - Hall element - Google Patents

Description

  The present invention relates to a Hall element used in a position detection device, and more specifically to a Hall element in which two Hall elements are formed in one chip.

  In recent years, in an imaging device such as a digital still camera or a digital video camera, high accuracy of several μm order is required for positioning control of an autofocus lens and a zoom lens with the increase in the number of pixels and the size of an image sensor such as a CCD. It has come to be. This is because, as the number of pixels of the image sensor is increased and the size is reduced, the out-of-focus blur due to the positioning error of the lens becomes more conspicuous. Therefore, in order to ensure the performance as the imaging device, a high degree of lens positioning accuracy is required. This is because that. In addition, with the downsizing of imaging devices such as digital still cameras and digital video cameras, further downsizing of position detection devices is required.

  In order to satisfy these requirements, a compact and highly accurate position detection device is provided by using a plurality of linear multipolar magnets in which magnetic poles that are reversed at a predetermined equal pitch are alternately arranged and a magnetic sensor such as a Hall element. Can be realized. In such a position detection device, two magnetic sensors are arranged with a gap of (1/4 + m) × λ, where λ is the magnetization pitch of the multipolar magnet. Here, m is an integer of 0 or more. Patent Document 1 describes that a position can be detected by obtaining a sine wave output from one of two magnetic sensors and a cosine wave output from the other by moving a multipolar magnet and calculating the value thereof. Has been.

  In the above position detection device, in order to improve the position detection accuracy, the amplitude of the sine wave output and the cosine wave output is made the same by using various operations and circuits, and the electrical angle phase difference between the sine wave output and the cosine wave output. It is known to make the angle exactly 90 °.

  A position detection device using two Hall elements as a magnetic sensor is described in Patent Document 2. As actual products utilizing the technical features of the invention, HQ-0221, HQ-0222, etc. manufactured by Asahi Kasei Electronics can be cited.

JP 2004-012745 A JP 2008-076194 A

  As can be seen in Patent Documents 1 and 2, in the conventional position detecting device, two Hall elements are formed in separate chips, respectively. Therefore, since two chips are used, there is a problem that the cost is high and the package cannot be made small.

  When performing position detection using two Hall elements, as shown in FIG. 1A, the input terminals of the two Hall elements are made common, and the output terminals are each taken out to be six terminals. Therefore, if a conventional chip that obtains one Hall element from one chip is used, the connection between the two Hall elements needs to be wired on the lead frame using 8 wires to be 6 terminals. was there. Alternatively, as shown in FIG. 1B, it is necessary to share inputs with external wiring as eight terminals. In either case, 8 wires are required.

  Furthermore, there is also a deterioration in detection accuracy due to position variations when placing each chip. For example, there has been a problem that positional deviation of the order of several tens of μm occurs as a positional deviation due to die bonding.

The present invention is a Hall element used in a position detection device, and the Hall element includes a first Hall element and a second Hall element formed on the same substrate, and the first Hall element and the second Hall element are provided. Are connected to a common power input terminal and a common GND terminal formed on the same plane on the substrate through wirings, and both the common power input terminal and the common GND terminal are connected to each other. The wiring and the electrode pad are formed as electrode patterns on the same plane on the same substrate, and when the Hall element is viewed in plan, the substrate is rectangular, and the first pad the flow direction a first signal input to the Hall element to a line connecting the area region and the GND terminal is connected to the power supply input terminal to the Hall element is connected, the base The long side axis of, but is an angle of 45 degrees, and the first a segment first area between the GND terminal of said power supply input terminal to the Hall element is connected to connecting a region that is connected A line segment connecting a direction in which a signal input to the Hall element flows and a region where the power input terminal is connected to the second Hall element and a region where the GND terminal is connected to the second Hall element. A direction in which a signal input to the element flows is orthogonal to the element .

  In one embodiment of the present invention, the first Hall element and the second Hall element are connected in parallel to the common power input terminal and the common GND terminal.

  In one embodiment of the present invention, the first Hall element and the second Hall element are made of a compound semiconductor.

  In one embodiment of the present invention, the position detection device includes a linearly moving magnet, and the direction in which a signal is input from the power supply input terminal common to the first Hall element is the first Hall element and the second Hall element. The surface on the substrate on which the Hall element is formed is inclined 45 degrees counterclockwise with respect to the axis along the direction of movement of the magnet, and a signal is input from the power supply input terminal common to the second Hall element The direction is inclined 45 degrees clockwise with respect to the axis along the direction in which the magnet moves on the surface on the substrate on which the first Hall element and the second Hall element are formed.

  According to the present invention, since two Hall elements are formed in one chip and the chip size can be reduced by an appropriate layout described later, the package size can be reduced.

  Furthermore, with regard to the arrangement of the two Hall elements, in the conventional two chips in which the two Hall elements are separately formed, the positional variation due to die bonding at the time of assembly deteriorated the gap accuracy between the Hall elements. On the other hand, in the present invention, since two Hall elements are simultaneously formed on the same chip by lithography, it is possible to solve the problem of the gap accuracy deterioration between the Hall elements as seen in the conventional two chips.

1A and 1B are wiring diagrams for connecting Hall elements according to an embodiment of the prior art. 2A and 2B are conceptual diagrams showing a position detection method using two Hall elements according to the present invention. It is a top view of the Hall element for position detection devices concerning one example of the present invention. It is a top view of the Hall element for position detection devices concerning the example of conventional technology. It is a figure which shows the manufacturing process of the Hall element for position detection apparatuses which concerns on one Example of this invention. It is a top view of the Hall element for position detection devices concerning another example of the present invention.

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

  FIG. 2A is a diagram illustrating an arrangement example of the multipolar magnet 23 and the two Hall elements (21, 22) in the position detection device. The position detection device includes a first Hall element 21, a second Hall element 22, and a linear multipolar magnet 23. The linear multipolar magnet 23 alternates magnetic poles at a predetermined equal pitch. Inverted and arranged. λ represents the magnetization pitch of the magnetic poles, and d represents the gap between the first Hall element 21 and the second Hall element 22. In the position detection device described in Patent Document 1, two magnetoelectric conversion elements are arranged at a distance of d = (1/4 + m) × λ (where m is an integer of 0 or more). FIG. 2A shows an arrangement when m = 0, that is, when d = 1/4 × λ.

  Here, the direction in which the multipolar magnet 23 moves is defined as the X axis, the direction perpendicular to the magnetized surface of the multipolar magnet 23 is defined as the Z axis, and the X axis and the axis perpendicular to the Z axis are defined as the Y axis. In the following drawings, the definition of the coordinates is common.

  By moving the multipolar magnet 23 in the X-axis direction in such an arrangement, for example, a sine wave output is obtained from the first Hall element 21 and a cosine wave output is obtained from the second Hall element 22, and the values are used. The position can be detected by calculating the above.

  FIG. 2B is a diagram illustrating an arrangement example of a magnet 24 having two magnetic poles and two Hall elements (21, 22) in the position detection device. This position detection device includes a first Hall element 21, a second Hall element 22, and a magnet 24 having two magnetic poles. In FIG. 2B, the solid line arrow represents the direction in which the magnet 24 moves, and the broken line arrow represents the magnetic field.

  The relative position with respect to the magnet is detected by calculating the output voltage obtained from the two hall elements by moving the magnet in the X-axis direction with the arrangement of the magnet and the hall element as shown in FIGS. 2A and 2B. can do.

  In the Hall element according to the present invention, two Hall elements are arranged with high precision, and particularly effective in combination with a multipolar magnet having a determined short magnetization pitch λ.

  In FIG. 2A, the pitch between adjacent N poles and N poles is defined as a magnetization pitch λ, because the Hall element can distinguish between N poles and S poles. Needless to say, in a magnetic sensor such as a resistance element that cannot discriminate between the N pole and the S pole, the pitch between the adjacent N pole and S pole is the magnetization pitch λ.

  In the present invention, two Hall elements (21, 22) are formed in one chip. This enables the closest arrangement of the Hall elements so that the gap d between the first Hall element 21 and the second Hall element 22 is minimized, that is, 1/4 × λ (m = 0). Become. On the other hand, when a conventional Hall element in which one Hall element is formed in one chip is used, two chips are used to realize the arrangement as shown in FIG. 2A. In the case of λ = 560 μm, it is impossible to arrange the Hall elements so that d is 1/4 × λ = 140 μm (m = 0), and at least (1/4 + 1) × λ = 700 μm (m = 1) The above gap was necessary. Accordingly, there is a problem that the package size becomes large, but such a problem is solved by the present invention.

  FIG. 3 is a plan view of a Hall element according to an embodiment of the present invention. Two Hall elements and six electrode pads (33, 34, 35, 36, 37, 38) are formed on the substrate 39. The first Hall element 31 and the second Hall element 32 are connected in parallel to an electrode pad 34 that is a common power input terminal and an electrode pad 38 that is a common GND terminal. As shown in FIG. 3, the direction in which a signal is input from the electrode pad 34, which is a power input terminal, to the first Hall element 31 is inclined 45 degrees counterclockwise with respect to the X axis. The direction in which a signal is input from the electrode pad 34 to the second Hall element 32 is inclined 45 degrees clockwise with respect to the X axis.

As a premise of the design in this example, the size of the sensitive part of the Hall elements (31, 32) was set to L = 90 μm, W ₁ = 30 μm, and L / W ₁ = 3. The first Hall elements (31, 32) having such a size correspond to a multipolar magnet having a magnetization pitch of λ = 560 μm, and constitute a position detection device together with the multipolar magnet. In addition, each of the electrode pads (33, 34, 35, 36, 37, 38) has a size in which a circle having a diameter of 75 μm is inscribed, and a distance between the centers of the pads is 120 μm or more. The width W ₂ of the wiring connecting the Hall elements (31, 32) and the electrode pads is 20 μm. Further, the electrode pattern composed of the electrode pad and the wiring was made to have a distance of at least 20 μm or more between the other electrode patterns, and the distance between the electrode pattern and the outer peripheral edge of the substrate 39 was secured to 15 μm or more.

  For comparison with the above embodiment, FIG. 4 shows a plan view of a Hall element according to an embodiment of the prior art. On the substrate 49, one Hall element 41 and four electrode pads (43, 44, 45, 46) are formed.

  Under the above assumption, the number obtained from a 4-inch wafer is 43300 when two elements are taken from one chip, and 18% compared with the number 36800 obtained when two elements are taken from two chips in the past. The number of picks increases.

  In addition, regarding the arrangement of the two Hall elements, in the case of the conventional two chips, the positional variation due to the die bonding at the time of assembly deteriorated the gap accuracy between the elements, whereas in the chip according to the present invention, two chips are obtained by lithography. Since the Hall elements are simultaneously formed on the same chip, the gap between the elements can be eliminated.

  Furthermore, in the present invention, since two Hall elements are connected to the same power input terminal and the same GND terminal in one chip, the number of electrode pads is six. Since the number of electrode pads can be reduced compared to the number of pads 8 (4 pads × 2 chips) in the case of the conventional two chips, the number of wires in the assembly can be reduced, and the efficiency of the assembly process is improved. .

  A manufacturing process of the Hall element for a position detecting device according to the present embodiment will be described with reference to FIG. First, an active layer 52 made of a compound semiconductor is formed on a GaAs substrate 51 by molecular beam epitaxy, and then a Hall element 53 is formed by etching by lithography. Next, after forming the protective film 54 by PCVD, the contact hole 55 is formed, and the electrode pattern 56 is formed by one deposition.

  The method of connecting the input terminal and the GND terminal between the first Hall element and the second Hall element in one chip can be performed in series or in parallel. In the case of parallel connection, it is possible to connect the sensing part and the electrode pad by multilayering the wiring, but it is more preferable to form the electrode pattern on the same plane as in the present invention because the process can be simplified. .

  FIG. 6 is a plan view of a Hall element according to another embodiment of the present invention. On the substrate 69, two Hall elements (61, 62) and six electrode pads (63, 64, 65, 66, 67, 68) are formed. The first Hall element 61 and the second Hall element 62 are connected in parallel to an electrode pad 65 that is a common power input terminal and an electrode pad 66 that is a common GND terminal. As shown in FIG. 6, the directions in which signals are input to the first Hall element 61 and the second Hall element 62 are both parallel to the Y axis (0 degree). In this case, the number obtained from a 4-inch wafer is 40300 when two elements are taken from one chip, and 9.5% of the number obtained when compared with 36800 when two elements are taken from the conventional two chips. Will increase.

21, 22, 31, 32, 41, 53, 61, 62 Hall element 23 Multipolar magnet 24 Magnets 33, 34, 35, 36, 37, 38, 43, 44, 45, 46, 63, 64, 65, 66 , 67, 68 Electrode pads 39, 49, 69 Substrate 51 GaAs substrate 52 Active layer 54 Protective film 55 Contact hole 56 Electrode pattern

Claims (4)

Hall element used in a position detection device,
The Hall element includes a first Hall element and a second Hall element formed on the same substrate,
The first Hall element and the second Hall element are respectively connected to a common power input terminal and a common GND terminal formed on the same plane on the same substrate via wirings,
The common power input terminal and the common GND terminal are both electrode pads, and the wiring and the electrode pads are formed as electrode patterns on the same plane on the same substrate,
When the Hall element is viewed in plan view,
The substrate is rectangular;
A line segment connecting a region where the power input terminal is connected to the first Hall element and a region where the GND terminal is connected, and a direction in which a signal input to the first Hall element flows, and the substrate A line segment connecting a region where the power input terminal is connected to the first Hall element and a region where the GND terminal is connected to the first Hall element . A line segment connecting a direction in which a signal input to the Hall element flows and a region where the power input terminal is connected to the second Hall element and a region where the GND terminal is connected to the second Hall element. A hall element characterized in that a direction in which a signal inputted to the element flows is orthogonal.   2. The Hall element according to claim 1, wherein the first Hall element and the second Hall element are connected in parallel to the common power supply input terminal and the common GND terminal.   The Hall element according to claim 1, wherein the first Hall element and the second Hall element are made of a compound semiconductor. The position detection device includes a linearly moving magnet,
The direction in which a signal is input to the first Hall element from the common power input terminal is such that the magnet moves on the surface on the substrate on which the first Hall element and the second Hall element are formed. Tilt 45 degrees counterclockwise with respect to the axis along the direction,
The direction in which a signal is input to the second Hall element from the common power input terminal is such that the magnet moves on the surface on the substrate on which the first Hall element and the second Hall element are formed. 4. The hall element according to claim 1, wherein the hall element is inclined 45 degrees clockwise with respect to an axis along the direction.

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