阅读说明：本技术 半导体装置 (Semiconductor device with a plurality of semiconductor chips ) 是由 小川洋平 上村紘崇 于 2020-03-27 设计创作，主要内容包括：半导体装置具备：包含对第1方向垂直的表面的半导体衬底；设置在半导体衬底的立式霍尔元件,其包含在第1方向具有深度、在对第1方向垂直的第2方向具有宽度、以及在与第1方向及第2方向的两个方向垂直的第3方向具有纵长的磁传感部；以及沿第3方向延伸的励磁布线,励磁布线在半导体衬底的表面侧配置在从第1方向的俯视观察下与磁传感部的宽度的中心重叠的位置,在将磁传感部的宽度设为W、将俯视观察下从磁传感部的宽度的中心到较近一侧的第1端面的距离设为Wc/2、将从磁传感部的深度的中心到励磁布线的距离设为h时,满足下述(1)式的关系的u为0.6以上。<Image he="70" wi="278" file="31231DEST_PATH_IMAGE002.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(The semiconductor device includes: a semiconductor substrate including a surface perpendicular to the 1 st direction; a vertical hall element provided on a semiconductor substrate, the vertical hall element including a magnetic sensor portion having a depth in a 1 st direction, a width in a 2 nd direction perpendicular to the 1 st direction, and a longitudinal length in a 3 rd direction perpendicular to both the 1 st direction and the 2 nd direction; and a field wiring extending in the 3 rd direction, the field wiring being disposed on the front surface side of the semiconductor substrate so as to overlap with the center of the width of the magnetic sensing part in a plan view from the 1 st directionWhen the width of the magnetic sensor unit is W, the distance from the center of the width of the magnetic sensor unit to the 1 st end surface on the closer side in a plan view is Wc/2, and the distance from the center of the depth of the magnetic sensor unit to the excitation wiring is h, u satisfying the relationship of the following expression (1) is 0.6 or more.)

1. A semiconductor device is characterized by comprising:

a semiconductor substrate comprising a surface perpendicular to a 1 st direction;

a vertical hall element provided on the semiconductor substrate, and including a magnetic sensor portion having a depth in the 1 st direction, a width in the 2 nd direction perpendicular to the 1 st direction, and a longitudinal length in the 3 rd direction perpendicular to both the 1 st direction and the 2 nd direction; and

an excitation wiring having a 1 st end surface and a 2 nd end surface in the 2 nd direction and extending in the 3 rd direction,

the excitation wiring is disposed on the front surface side of the semiconductor substrate at a position separated from the magnetic sensor unit and at a position overlapping the center of the width of the magnetic sensor unit in a plan view in the 1 st direction,

the position where the excitation wiring is disposed is a position where a distance from a center of a width of the magnetic sensor portion to the 1 st end face is equal to or less than a distance from the center of the width of the magnetic sensor portion to the 2 nd end face in the plan view,

when the width of the magnetic sensor unit is W, the distance from the center of the width of the magnetic sensor unit to the 1 st end surface in the plan view is Wc/2, and the distance from the center of the depth of the magnetic sensor unit to the excitation wiring is h, u derived from the following expression (1) is 0.6 or more.

2. The semiconductor device according to claim 1, wherein: the excitation wiring covers the magnetic sensor portion in the plan view.

3. The semiconductor device according to claim 1 or 2, wherein: the excitation wiring is disposed at a position where a center of the excitation wiring in the 2 nd direction overlaps a center of the magnetic sensor portion in the 2 nd direction in the plan view.

Technical Field

The present invention relates to a semiconductor device.

Background

For example, there is a semiconductor device using a hall element as a magnetic sensor. Hall elements are used in various applications as magnetic sensors capable of detecting a position or an angle in a non-contact manner. In addition, the hall element has a vertical hall element and a horizontal hall element. Among them, the horizontal hall element is a magnetic sensor that detects a magnetic field component perpendicular to the element surface. On the other hand, the vertical hall element is a magnetic sensor that detects a magnetic field component parallel to the element surface. Further, a magnetic sensor has been proposed in which a horizontal hall element and a vertical hall element are combined to detect a magnetic field two-dimensionally or three-dimensionally.

However, the vertical hall element is more susceptible to manufacturing variations than the horizontal hall element, and the variations in sensitivity and bias voltage characteristics are more likely to increase than the horizontal hall element.

In order to correct such characteristic variations, a method has been proposed in which an excitation wire is disposed in the vicinity of the vertical hall element, a constant current is passed through the excitation wire, a magnetic field having a predetermined intensity (hereinafter referred to as a "correction magnetic field") is applied to the magnetic sensing unit of the vertical hall element, and the sensitivity of the magnetic sensing unit is estimated (see, for example, patent document 1). That is, in the invention described in patent document 1, the actual sensitivity of the magnetic sensor unit is estimated by changing the intensity of the correction magnetic field and measuring the change in the hall voltage output from the vertical hall element.

In the invention described in patent document 1, an operation of shifting the center of the excitation wire in the horizontal direction with respect to the center of the magnetic sensor unit in the vertical hall element, that is, an operation of separating the center of the excitation wire and the center of the magnetic sensor unit in the horizontal direction is performed. This suppresses variation in the intensity of the correction magnetic field generated by the excitation wiring due to variation in the width of the excitation wiring or the like caused by process variation in the manufacturing process of the semiconductor device.

[ Prior art documents ]

[ patent document ]

[ patent document 1 ] specification of U.S. Pat. No. 9116192.

Disclosure of Invention

[ problem to be solved by the invention ]

However, in the invention described in patent document 1, since the magnetic field wiring and the magnetic sensor unit are disposed to be separated from each other in the horizontal direction, the following problem occurs. The intensity of the correction magnetic field generated by the current flowing through the excitation wiring is inversely proportional to the distance from the excitation wiring, and therefore the intensity of the correction magnetic field applied to the magnetic sensing unit decreases as the distance between the magnetic sensing unit and the excitation wiring increases.

When the intensity of the correction magnetic field applied to the magnetic sensor unit is low, the variation of the hall voltage output from the vertical hall element is small. Therefore, in the invention described in patent document 1, even if the variation in the intensity of the correction magnetic field applied to the magnetic sensor unit can be suppressed, the accuracy of estimating the actual sensitivity in the magnetic sensor unit is degraded because the intensity of the correction magnetic field is low.

As a countermeasure, it is conceivable to increase the current flowing through the excitation wiring to increase the intensity of the correction magnetic field applied to the magnetic sensor unit. However, if the current flowing through the excitation wiring is increased, the amount of heat generation of the excitation wiring increases.

In the invention described in patent document 1, the center of the excitation wiring is greatly offset from the center of the magnetic sensor unit in the horizontal direction, and therefore the distance between the excitation wiring and the peripheral circuit disposed around the magnetic sensor unit is reduced. In this case, the peripheral circuit is affected by heat from the close excitation wiring. Specifically, an asymmetrical temperature distribution occurs in the peripheral circuit due to heat generation of the excitation wiring, and the characteristics of the peripheral circuit fluctuate. Therefore, when the current flowing through the excitation wiring is increased, the accuracy of estimating the actual sensitivity of the magnetic sensor unit is also reduced.

Further, if the distance between the excitation wiring and the peripheral circuit is increased, the characteristic variation of the peripheral circuit can be suppressed, but the required area of the semiconductor device is increased, which leads to an increase in cost, and thus is not practical.

The invention aims to provide a semiconductor device which improves the generation efficiency of a correction magnetic field applied to a magnetic sensing part and suppresses the variation of the intensity of the correction magnetic field and the characteristic variation caused by the heat of a peripheral circuit.

[ MEANS FOR solving PROBLEMS ] A method for solving the problems

In order to achieve the above object, a semiconductor device according to an embodiment of the present invention includes: a semiconductor substrate comprising a surface perpendicular to a 1 st direction; a vertical hall element provided on a semiconductor substrate, including a magnetic sensor section having a depth in a 1 st direction, a width in a 2 nd direction perpendicular to the 1 st direction, and a longitudinal length in a 3 rd direction perpendicular to both the 1 st direction and the 2 nd direction; and an excitation wiring having a 1 st end face and a 2 nd end face in a 2 nd direction and extending in a 3 rd direction, the excitation wiring being disposed on a surface side of the semiconductor substrate at a position spaced apart from the magnetic sensing unit and at a position overlapping a center of a width of the magnetic sensing unit in a 1 st direction in a plan view, the position at which the excitation wiring is disposed being a position where a distance from the center of the width of the magnetic sensing unit to the 1 st end face is equal to or less than a distance from the center of the width of the magnetic sensing unit to the 2 nd end face in the plan view, and when the width of the magnetic sensing unit is represented by W, a distance from the center of the width of the magnetic sensing unit to the 1 st end face in the plan view is represented by Wc/2, and a distance from the center of a depth of the magnetic sensing unit to the excitation wiring is represented by h, u derived from the following expression (1) is 0.6 or more.

[ Effect of the invention ]

According to the semiconductor device of the present invention, the excitation wiring for generating the calibration magnetic field and the magnetic sensor unit are disposed in an appropriate relationship, whereby the efficiency of generating the calibration magnetic field applied to the magnetic sensor unit can be improved, and variations in intensity and characteristic variations due to heat of peripheral circuits can be suppressed.

Drawings

Fig. 1 is a plan view showing the structure of a semiconductor device according to embodiment 1.

Fig. 2 is a sectional view of the semiconductor device according to the present embodiment taken along line II-II.

Fig. 3 is a sectional view of a main part of a III-III line of the semiconductor device according to the present embodiment.

Fig. 4 is an explanatory diagram illustrating the principle of the semiconductor device according to the embodiment.

Fig. 5 is a graph showing the intensity distribution of the correction magnetic field applied to the magnetic sensing section along the two-dot chain line C shown in fig. 2.

Fig. 6 is a graph showing the relationship between the uniformity and the intensity deviation of the correction magnetic field applied to the magnetic sensing section.

Fig. 7 is a plan view showing the structure of the semiconductor device according to embodiment 2.

Fig. 8 is a sectional view of the semiconductor device according to the present embodiment taken along line VIII-VIII.

Detailed Description

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

In addition, in the drawings used in the following description, for the sake of easy understanding of the features, the portions that become the features are enlarged and shown, and the dimensional ratios of the respective components and the like may be different from those in reality. In the following description, directions such as left, right, up, and down are directions based on the illustrated state.

(embodiment 1)

Fig. 1 is a plan view showing the structure of a semiconductor device 1A according to embodiment 1 of the present invention. Fig. 2 is a sectional view (sectional view of line II-II) taken along a cutting line II-II shown in fig. 1 of the semiconductor device 1A. Fig. 3 is a sectional view of a main portion of the semiconductor device 1A along a cutting line III-III shown in fig. 1 (a sectional view of a main portion of the line III-III). Note that fig. 1 shows a state where the insulating layers 6a and 6b are omitted for convenience of description.

As shown in fig. 1, 2, and 3, the semiconductor device 1A includes: a semiconductor substrate 2; a vertical hall element 3 including a magnetic sensor portion 3a and provided on the semiconductor substrate 2; and an excitation wiring 4 provided above the magnetic sensor portion 3 a.

The semiconductor substrate 2 has a 1 st conductivity type (e.g., P-type) which is one of P-type and N-type. In addition, the semiconductor substrate 2 includes a surface S perpendicular to the depth direction as the 1 st direction. Here, the depth direction in the 1 st direction is also a direction parallel to the z direction of the xyz three-dimensional orthogonal coordinate system. The vertical hall element 3 and the diffusion layer 8 are provided on the semiconductor substrate 2.

The vertical hall element 3 includes a magnetic sensor portion 3a that detects a magnetic field component parallel to the element surface, and a plurality of (for example, 5 in the present embodiment) electrodes 7 arranged above the magnetic sensor portion 3 a. The electrodes 7 have a predetermined length (width) in the width direction as the 2 nd direction and are arranged side by side in the longitudinal direction as the 3 rd direction. Here, the width direction is a direction perpendicular to the depth direction, and is a direction parallel to the x direction. The longitudinal direction is a direction perpendicular to both the depth direction and the width direction, and is a direction parallel to the y direction.

The magnetic sensor portion 3a is a semiconductor layer (well) provided by, for example, implanting an impurity of the 2 nd conductivity type (for example, N type), which is the other of the P type and the N type, into the semiconductor substrate 2 having the 1 st conductivity type. The magnetic sensor portion 3a is formed in a three-dimensional shape having a predetermined longitudinal length, width and depth. The magnetic sensor portion 3a has an end surface 3aR and an end surface 3aL opposed to each other in the width direction. The distance between the end surface 3aR and the end surface 3aL corresponds to the width W of the magnetic sensor portion 3 a. A line connecting the widthwise centers of the two end surfaces 3aR and 3aL is a widthwise center line of the magnetic sensor portion 3 a. The center line in the width direction of the magnetic sensor portion 3a extends in the longitudinal direction.

The magnetic sensor section 3a illustrated in fig. 1 to 3 has a width W (W > 0), a depth T (T > 0) from the surface S, and a longitudinal length longer than the width W. Further, the depth T is set to be shorter than the length of the semiconductor substrate 2 in the depth direction.

The magnetic sensor portion 3a has a function of detecting a magnetic field component in the width direction. When a magnetic field component in the width direction is applied to the magnetic sensor portion 3a, the vertical hall element 3 outputs a hall voltage corresponding to the magnetic field component between the electrodes 7.

The vertical hall element 3 is electrically separated from the other region of the semiconductor substrate 2 by the diffusion layer 8 provided so as to surround the periphery of the magnetic sensor portion 3 a. In addition, in other regions of the semiconductor substrate 2, a circuit for processing an output signal from the vertical hall element 3, a circuit for supplying a current to the vertical hall element 3, a circuit for compensating for the characteristics of the vertical hall element 3 by correcting a magnetic field, and the like are provided as peripheral circuits.

Insulating layers 6a and 6b are stacked on the surface S of the semiconductor substrate 2. The insulating layer 6b is provided so as to cover the surface S of the semiconductor substrate 2. The excitation wiring 4 is provided on the insulating layer 6 b. The excitation wiring 4 is electrically separated from the vertical hall element 3 by an insulating layer 6 b. The insulating layer 6a is provided on the insulating layer 6b so as to cover the excitation wiring 4.

The excitation wiring 4 is provided on the surface S side of the semiconductor substrate 2 apart from the magnetic sensor unit 3 a. The excitation wiring 4 has an end face 4R as a 1 st end face and an end face 4L as a 2 nd end face in the width direction, and extends in the longitudinal direction. The distance between the end face 4R and the end face 4L corresponds to the width of the excitation wiring 4. A line connecting the centers, which are the midpoints in the width direction of the end surfaces 4R and 4L, constitutes a center line in the width direction of the excitation wiring 4. The center line in the width direction of the excitation wiring 4 extends in the longitudinal direction. The excitation wiring 4 is connected to a power supply not shown.

The positional relationship between the excitation wiring 4 and the magnetic sensor portion 3a will be described in detail. In the semiconductor device 1A, the position where the excitation wiring 4 is arranged is determined so that the excitation wiring 4 and the magnetic sensor unit 3a have a predetermined positional relationship. The excitation wiring 4 has a lower surface located on the surface S side of the semiconductor substrate 2 in the depth direction. The excitation wiring 4 is arranged at the following positions in the depth direction: the magnetic sensor section 3a is spaced apart from the lower surface of the excitation wiring 4 by a distance h from the center in the depth direction thereof, i.e., a position of a depth T/2 1/2 times the depth T of the magnetic sensor section 3 a. The position of the depth T/2 of the magnetic sensor portion 3a is shown by a two-dot chain line C in fig. 2 and 3.

Here, for the sake of simplicity of explanation, the center in the width direction of the magnetic sensor portion 3a is referred to as "the center in the width direction of the magnetic sensor portion 3 a". In addition, in a plan view in the depth direction, a distance from the center of the magnetic sensor unit 3a in the width direction to the opposite end surfaces of the excitation wiring 4 in the width direction to the closer or equal end surface is referred to as a "1 st distance", and a distance to the farther or equal end surface is referred to as a "2 nd distance". Further, distance 1 defines distance Wc/2.

In the semiconductor device 1A, the position where the excitation wiring 4 is arranged is determined based on an index (hereinafter, referred to as "uniformity") u of the following expression (1). More specifically, the excitation wiring 4 is disposed at a position where the uniformity u is 0.6 or more. The uniformity u is expressed by the following expression (1) using the distance Wc/2 corresponding to the 1 st distance, the width W of the magnetic sensor unit 3a, and the distance h.

Further, the excitation wiring 4 is disposed at a position where the 1 st distance and the 2 nd distance are equal in a plan view in the depth direction. The position of the excitation wiring 4 is a position where the center line of the excitation wiring 4 in the width direction coincides with the center line of the magnetic sensor unit 3a in the width direction. In other words, the excitation wiring 4 is disposed at a position symmetrical with respect to the center line in the width direction of the magnetic sensor portion 3a in a plan view in the depth direction.

Next, the technical meaning of the above formula (1) will be described with reference to fig. 4.

Fig. 4 (a) is an explanatory diagram in which the magnetic sensor unit 3a and the excitation wiring 4 in the configuration shown in fig. 2 are drawn out to show the positional relationship between the magnetic sensor unit 3a and the excitation wiring 4. The two-dot chain line C shown in fig. 4 (a) indicates the position of the depth T/2 of the magnetic sensor portion 3 a. The two-dot chain line C and the center line in the width direction of the magnetic sensing part 3a, the end surface 3aR, and the end surface 3aL are at the point X₀Point X_RAnd point X_LAnd (4) intersecting.

First, in describing the technical meaning of the above expression (1), coordinates xs are set. The point X which is the intersection of the two-dot chain line C and the center line of the magnetic sensor unit 3a in the width direction of the coordinate xs₀Is set as a reference. I.e. when xs is 0, coordinate xs and point X₀And (5) the consistency is achieved. The coordinate xs is along the two-dot chain line C away from the point X₀The direction of (c) takes a numerical value. The numerical value of the coordinate xs represents a point on the two-dot chain line C to a point X₀The distance of (c).

In the configuration of fig. 4 (a), the magnetic field strength Bs at the coordinate xs of the correction magnetic field generated when the current of the current density j flows through the excitation wiring 4 is represented by the following expression (2). Here, α is a coefficient.

The uniformity in the width direction of the intensity of the correction magnetic field applied to the magnetic sensor section 3a can be evaluated by comparing the magnitudes of the intensities of the correction magnetic field at two points, i.e., the point where the magnitude is the largest and the point where the magnitude is the smallest, on the two-dot chain line C in the magnetic sensor section 3 a. In the magnetic sensor unit 3a in the positional relationship illustrated in fig. 4 (a), the point X is set to be the same as the point X_RAnd point X_LAre located at symmetrical positions with respect to the center in the width direction of the excitation wiring 4. In the case of the intensity Bs of the correction magnetic field generated by the excitation wiring 4, the magnitude of the X-direction component thereof is at the point X located at the center in the width direction₀Becomes maximum at point X_RAnd point X_LThese two points are the smallest. Thus, by comparing point X₀Magnitude of the intensity of the corrective magnetic field above and point X_ROr point X_LThe magnitude of the intensity of the correction magnetic field in (3 a) can evaluate the uniformity of the intensity of the correction magnetic field in the width direction in the magnetic sensor section 3 a.

Next, a case will be described where 1 point on the two-dot chain line C in the magnetic sensor section 3a at which the magnitude of the x-direction component of the intensity of the correction magnetic field is the smallest is provided.

The case where the number of points at which the magnitude of the x-direction component of the intensity of the correction magnetic field becomes minimum is 1 means the case where the 1 st distance is smaller than the 2 nd distance, that is, the case where the 1 st distance and the 2 nd distance are not equal. This configuration is theoretically equivalent to a configuration in which the excitation wiring 14 equivalent to the excitation wiring 4 is additionally provided to the excitation wiring 4 in the width direction. Therefore, a case where the magnitude of the x-direction component of the intensity of the correction magnetic field is minimized to 1 point will be described by taking, as an example, a configuration in which the excitation wiring 14 is additionally provided to the excitation wiring 4 in the width direction.

Fig. 4 (b) is an explanatory diagram showing the positional relationship between the magnetic sensor section 3a and the excitation wiring 24 (excitation wirings 4 and 14) obtained by performing modulo on the case where the point at which the magnitude of the x-direction component of the intensity of the correction magnetic field becomes minimum is 1.

The excitation wiring 14 has right and left end faces 14L facing each other in the width direction, and the right end face is disposed in contact with the left end face of the excitation wiring 4. The sum of the correction magnetic fields generated by the excitation wiring 4 and the excitation wiring 14 is equal to the correction magnetic field generated by 1 excitation wiring 24. Therefore, when a current flows through the excitation wiring 14 at the same current density as the excitation wiring 4, the excitation wiring 4 and the excitation wiring 14 can be regarded as 1 excitation wiring 24.

If the excitation wiring 4 and the excitation wiring 14 are regarded as 1 excitation wiring 24, the distance Wc/2 from the center of the magnetic sensor unit 3a in the width direction to the end surface 4R becomes the 1 st distance with respect to the excitation wiring 24, and the distance from the center of the magnetic sensor unit 3a in the width direction to the end surface 14L becomes the 2 nd distance with respect to the excitation wiring 24. In this case, the 1 st distance is smaller than the 2 nd distance. Therefore, the center of the excitation wiring 24 in the width direction does not coincide with the center of the magnetic sensor section 3a in the width direction. I.e. point X_RAnd point X_LIs located asymmetrically with respect to the center of the width direction of the excitation wiring 24. The intensity distribution of the intensity Bas of the correction magnetic field generated by the excitation wiring 24 is different from the intensity Bs of the correction magnetic field generated by the excitation wiring 4.

As described above, the uniformity in the width direction of the intensity Bas of the calibration magnetic field applied to the magnetic sensor section 3a can be evaluated by comparing the magnitudes of the intensities of the calibration magnetic field at two points, i.e., the point on the two-dot chain line C where the magnitude is the largest and the point on the two-dot chain line C where the magnitude is the smallest. In thatHere, in the magnetic sensor unit 3a having the positional relationship illustrated in fig. 4 (b), the intensity of the correction magnetic field formed by the excitation wiring 14 is applied to the point X_R、X_LThe strength of the correction magnetic field of (2) brings about an influence. About point X_R、X_LThe influence of the intensity of the correction magnetic field is shown at a point X closer to the excitation wiring 14_LPoint X of relatively greater upper and greater distance_RThe upper phase is relatively small. Thus, point X_LHas a magnetic field strength greater than point X_RAnd becomes closer to the point X₀The magnitude of the intensity of the corrective magnetic field. That is, in the magnetic sensor unit 3a illustrated in fig. 4 (b), the magnitude of the X-direction component of the intensity of the correction magnetic field is at the point X_RThe upper becomes the smallest.

In addition, when the end face 14L is disposed in contact with the end face 4R, the right and left directions are reversed with respect to the case where the right end face of the excitation wiring 14 is disposed in contact with the left end face of the excitation wiring 4. That is, in this case, the magnitude of the X-direction component of the intensity of the correction magnetic field is at point X_LThe upper becomes the smallest.

When the uniformity u represented by the above expression (1) is 0.6 or more, the maximum value of the X-direction component of the intensity of the correction magnetic field in the magnetic sensor unit 3a and the point X₀The strength of the corrective magnetic field above is substantially uniform. On the other hand, in both cases where the excitation wiring 14 is disposed in contact with either one of the left and right end faces of the excitation wiring 4, the point X is the point X_RAnd X_LA point at which the magnitude of the x-direction component of the intensity of the correction magnetic field becomes minimum appears.

As described above, when the 1 st distance and the 2 nd distance are equal to each other (in the case of fig. 4 (a)), the point of the magnetic sensor unit 3a at which the magnitude of the X-direction component of the intensity of the correction magnetic field becomes minimum is the point X_RAnd X_LTwo of these. In the case where the 1 st distance is smaller than the 2 nd distance (in the case of fig. 4 (b)), the magnitude of the X-direction component of the intensity of the correction magnetic field in the magnetic sensor portion 3a becomes minimum, which is the point X_R、X_LOf the magnetic sensor parts 3a, and excitation of the excitation wiring 4 with respect to the center in the width direction of the magnetic sensor part 3aA point on the side where the end face of the wiring 14 which is not in contact is located. In other words, the point is a point on the side where the end surface closer to the center in the width direction of the magnetic sensor unit 3a is located, among the two end surfaces in the width direction of the excitation wiring 24.

Therefore, as shown in fig. 4 (b), when the right end surface of the excitation wiring 14 and the left end surface of the excitation wiring 4 are disposed in contact with each other, the point at which the magnitude of the X-direction component of the intensity of the correction magnetic field in the magnetic sensor unit 3a becomes minimum is the point X_R. On the contrary, when the left end surface of the excitation wire 14 is disposed in contact with the right end surface of the excitation wire 4, the point at which the magnitude of the X-direction component of the intensity of the correction magnetic field in the magnetic sensor unit 3a becomes minimum is the point X_L。

According to the above-described study, it can be said that the uniformity in the width direction of the intensity of the calibration magnetic field in the magnetic sensor unit 3a can be obtained by comparing the point X of the magnetic sensor unit 3a in both the cases of fig. 4 (a) and 4 (b)₀The intensity of the upper correction magnetic field is set to a point X at a position spaced from the width direction center of the magnetic sensor unit 3a by a 1 st distance in the width direction_ROr point X_LThe intensity of the correction magnetic field above. In particular, when the uniformity u is 0.6 or more, the correction magnetic field applying point X formed by the excitation wiring 14₀Point X_LOr X_RSince the influence of the intensity of the correction magnetic field is small, the uniformity of the intensity Bas of the correction magnetic field formed by the excitation wiring 24 can be approximated by the uniformity of the intensity Bs of the correction magnetic field in the case of considering only the excitation wiring 4.

A current flows through the excitation wirings 4, 24, thereby generating a correction magnetic field around the excitation wirings 4, 24. The correction magnetic field is applied to the magnetic sensor section 3 a. The strength of the correction magnetic field is proportional to the magnitude of the current density flowing through the excitation wiring 4, 24. In addition, the strength of the correction magnetic field is inversely proportional to the distance to the excitation wirings 4, 24. The intensities Bs, Bas of the correction magnetic field at the coordinates xs on the two-dot chain line C are represented by the above expression (2). The sensing sensitivity of the vertical hall element 3 is estimated based on the calculation result of the intensity Bs or Bas of the correction magnetic field represented by the formula (2).

The excitation wirings 4 and 24 are preferably arranged to extend in the longitudinal direction parallel to the y direction. With this configuration, the intensities Bs and Bas of the calibration magnetic fields applied to the magnetic sensor unit 3a by the excitation wires 4 and 24 are equal in the longitudinal direction of the magnetic sensor unit 3 a.

The uniformity u shown by the above formula (1) corresponds to the point X obtained by dividing the intensity of the calibration magnetic field at the end surface 3aR by the center in the width direction of the magnetic sensor section 3a₀The strength of the correction magnetic field. The value of the uniformity u is 0 < u.ltoreq.1, and the closer to 1, the higher the uniformity of the intensity of the correction magnetic field applied to the magnetic sensor section 3a, and the closer to 0, the lower the uniformity of the intensity of the correction magnetic field applied to the magnetic sensor section 3 a.

As described above, the excitation wiring 4 may be disposed so that at least a part thereof overlaps the center of the magnetic sensor section 3a in the width direction in a plan view in the depth direction, but is preferably disposed so as to cover the magnetic sensor section 3a rather than overlapping a part of the magnetic sensor section 3 a. The appropriate range of the relationship between the distance Wc/2 and the width W of the magnetic sensor unit 3a differs depending on the relationship between the width W of the magnetic sensor unit 3a and the distance h.

For example, if h/W is 0.3, Wc/W is preferably 1 or more, and more preferably 1.4 or more. If h/W is 0.5, Wc/W is preferably 0.7 or more, and more preferably 1.4 or more. When h/W is 0.1, Wc/W is preferably 1.05 or more, more preferably 1.2 or more. The above-mentioned suitable range can be achieved by making the uniformity u 0.6 or more.

Fig. 5 is a graph showing the results of simulation of the distribution of the intensity of the correction magnetic field in the magnetic sensor section 3a along the two-dot chain line C shown in fig. 2 when the distance Wc/2 is changed in the semiconductor device 1A. The horizontal axis is the coordinate xs and the vertical axis is the strength of the correction magnetic field.

With respect to 2 cases where the distance Wc is 20 μm and 30 μm, the intensity of the correction magnetic field is shown in the case where the distance h to the lower surface of the excitation wiring 4 is 2.2 μm. In the semiconductor device 1A, the 1 st distance is equal to the 2 nd distance, and therefore the distance Wc corresponds to the width of the excitation wiring 4.

The magnetic field intensity distribution has a point X₀Occurring in the vicinityA region RA having a relatively gentle gradient and a region RB having a relatively steeper gradient than the region RA. Fig. 5 is a graph showing the region RA and the region RB in the case where the distance Wc corresponding to the width of the excitation wiring 4 is 30 μm.

Fig. 5 illustrates the magnetic field intensity distribution when the distance h is 2.2 μm in the case where the distance Wc is 20 μm and 30 μm, respectively, but the region RA and the region RB exist in any magnetic field intensity distribution. In addition, it was confirmed that when the distance Wc and the distance h other than the exemplified conditions are adopted, the size and gradient of the region RA and the region RB are also different, but the distance Wc and the distance h are present at any value. Accordingly, it can be said that the uniformity u can be improved by determining the width W of the magnetic sensor portion 3a so as to be within the region RA.

For example, when Wc is 30 μm and h is 2.2 μm, it can be estimated based on fig. 5 that the uniformity u is high when the width W of the magnetic sensor section 3a is less than 20 μm (2 times the 10 μm of the region RA in fig. 5).

This means that by selecting the distance Wc, the width W, and the distance h so as to converge the magnetic sensor section 3a within the region RA, the uniformity u on the magnetic sensor section 3a becomes high.

By arranging the magnetic sensor section 3a and the excitation wiring 4 so that the uniformity u becomes 0.6 or more, the correction magnetic field in the region RA can be mainly applied to the magnetic sensor section 3a, and the influence of the correction magnetic field in the region RB can be sufficiently reduced. The semiconductor device 1A includes the magnetic sensor unit 3a and the excitation wiring 4 arranged in this manner, and thus, variations in the correction magnetic field applied to the magnetic sensor unit 3a can be reduced. The reason for this will be described below.

When the value of the uniformity u is small, the end surfaces 3aR and 3aL in the width direction of the magnetic sensor section 3a are included in the region RB. When the end surfaces 3aR and 3aL are included in the region RB, if the width W of the magnetic sensor portion 3a varies due to a manufacturing process or the like, the intensities of the correction magnetic fields applied to the end surfaces 3aR and 3aL vary greatly. As a result, the total amount of the correction magnetic field applied to the magnetic sensor unit 3a changes rapidly.

Fig. 6 shows the simulation result of the variation in the deviation ratio of the magnetic field strength B with respect to the uniformity of the strength of the correction magnetic field. More specifically, the graph shows the results of a simulation in which Δ B represents the deviation amount of the magnetic field strength B when the width W of the magnetic sensor portion 3a is deviated to within 5% of the width W, and Δ B/B (hereinafter referred to as "magnetic field strength deviation") [% ] representing the deviation ratio of the magnetic field strength B when the uniformity u of the intensity of the correction magnetic field is changed is simulated in the semiconductor device 1A.

The horizontal axis represents the uniformity u and the vertical axis represents the magnetic field strength deviation Δ B/B. The uniformity u was varied by adjusting (Wc/2) in the above equation (1) while keeping the distances h constant at 4 μm, 6 μm, and 8 μm, respectively. The magnetic field strength B that becomes the reference of the magnetic field strength deviation Δ B/B is an average value of the magnetic field strength between the end surface 3aR and the end surface 3aL when the width W of the magnetic sensor portion 3a is 20 μm. The magnetic field strength deviation Δ B/B is a simulation result when the deviation is within ± 5% of the width W of 20 μm, that is, 19 μm W21 μm, based on the average value. The variation in the width W of the magnetic sensor portion 3a is determined by, for example, a diffusion step after impurity implantation, a depletion layer width in bonding with a diffusion layer, a test temperature, and the like.

The magnetic field strength deviation Δ B/B shown in FIG. 6 sharply increases at a uniformity u of less than 0.6 in the case where the distance h is 8 μm. It was confirmed that the same tendency as that in the case where the distance h was 8 μm was observed in the cases where the distance h was 6 μm and 4 μm. The magnetic field strength deviation Δ B/B sharply increases at a uniformity u of less than 0.55 in the case of a distance h of 6 μm, and sharply increases at a uniformity u of less than 0.5 in the case of a distance h of 4 μm.

The range of uniformity u in which the magnetic field strength deviation Δ B/B sharply increases corresponds to a case where one end of the magnetic sensor section 3a is included in the region RB, when the relationship with the graph shown in fig. 5 is described. Therefore, in order to suppress a rapid increase in the magnetic field strength deviation Δ B/B, the semiconductor device 1A may be configured so that only the correction magnetic field of the region RA is applied to the magnetic sensor unit 3 a. That is, the semiconductor device 1A may be configured such that the uniformity u is 0.6 or more.

As described above, in the semiconductor device 1A, the uniformity u is set to 0.6 or more, and the correction magnetic field of the region RA alone can be applied to the magnetic sensor unit 3 a.

The semiconductor device according to the present embodiment, including the above configuration, can suppress variations in the intensity of the correction magnetic field applied to the magnetic sensor unit 3 a. In addition, according to the semiconductor device of the present embodiment, the distance between the excitation wiring 4 and the magnetic sensor unit 3a in the width direction can be shortened, and thus the magnetic field generation efficiency is high. Further, according to the semiconductor device of the present embodiment, since the excitation wire 4 can be arranged at a position close to the center in the width direction of the magnetic sensor unit 3a, the excitation wire 4 can be separated from the peripheral circuit, and the thermal influence of the heat generation of the excitation wire 4 on the peripheral circuit can be reduced. Therefore, according to the semiconductor device of the present embodiment, it is possible to suppress characteristic variations due to heat of the peripheral circuit, such as an asymmetric temperature distribution occurring in the peripheral circuit. Therefore, according to the semiconductor device of the present embodiment, the sensing sensitivity of the vertical hall element 3 can be estimated with high accuracy.

(embodiment 2)

Fig. 7 is a plan view showing the structure of a semiconductor device 1B according to embodiment 2. Fig. 8 is a sectional view of the semiconductor device 1B taken along a cutting line VIII-VIII shown in fig. 7 (a sectional view taken along line VIII-VIII). In fig. 7, for convenience of explanation, the insulating layers 6a and 6b are omitted.

The semiconductor device 1B is different from the semiconductor device 1A in that the excitation wiring 24 is provided instead of the excitation wiring 4, and is substantially the same in other respects. In the following description, the same portions as those of the semiconductor device 1A are denoted by the same reference numerals, and redundant description thereof is omitted.

The excitation wiring 24 has an end surface 24R as a 1 st end surface and an end surface 24L as a 2 nd end surface in the width direction, and extends in the longitudinal direction, similarly to the excitation wiring 4. The excitation wiring 24 is disposed at a position where the distance from the center of the magnetic sensor unit 3a in the width direction to the end surface 24R is a distance Wc/2. The excitation wiring 24 is disposed at a position where the distance from the width direction center of the magnetic sensor section 3a to the end surface 24R is shorter than the distance from the width direction center of the magnetic sensor section 3a to the end surface 24L. That is, in the semiconductor device 1B, the excitation wiring 24 is disposed such that the distance Wc/2 from the center of the magnetic sensor unit 3a in the width direction to the end surface 24R becomes the 1 st distance and the distance from the center of the magnetic sensor unit 3a in the width direction to the end surface 24L becomes the 2 nd distance.

In the above arrangement, the point X located at the center in the width direction of the magnetic sensor portion 3a in plan view₀Overlaps with at least a part of the excitation wiring 24, but does not coincide with the center of the excitation wiring 24 in the width direction. That is, in the semiconductor device 1B, the excitation wiring 24 is disposed asymmetrically with respect to the center line in the width direction of the magnetic sensor portion 3a in a plan view.

The semiconductor device 1B is configured such that the uniformity u expressed by the above expression (1), which is determined by the distance Wc/2 corresponding to the 1 st distance of the excitation wiring 24, the width W of the magnetic sensor unit 3a, and the distance h from the center of the magnetic sensor unit 3a in the depth direction to the lower surface of the excitation wiring 24, is 0.6 or more. In the present embodiment, the uniformity u represented by the above expression (1) is the point X_RThe strength of the applied corrective magnetic field divided by the applied point X₀At point X, the value of the intensity of the correction magnetic field_RIs a point X where a point on the end surfaces 3aL, 3aR in the width direction of the magnetic sensing part 3a intersects with the two-dot chain line C_L、X_RAmong them, at a point on the farther side from the center in the width direction of the excitation wiring 24.

Here, for simplicity of explanation, referring to fig. 4 (b), as described above, the excitation wiring 24 is regarded as being constituted by the excitation wiring 4 and the excitation wiring 14, and a portion corresponding to the excitation wiring 4 is referred to as a "symmetric portion", and a portion corresponding to the excitation wiring 14 is referred to as an "asymmetric portion".

Since the semiconductor device 1B is configured to have the uniformity u of 0.6 or more, the correction magnetic field applying point X formed by the current flowing through the asymmetry portion in the excitation wiring 24 is as described above₀Point X_LOr X_RThe influence of the strength of the correction magnetic field on is small. Therefore, the uniformity of the intensity Bas of the correction magnetic field formed by the excitation wiring 24 having the asymmetrical portion in addition to the symmetrical portion can be made by considering only the excitation wiring 4The uniformity of the strength Bs of the correction magnetic field in the case is approximated.

As described above, in the semiconductor device 1B, the correction magnetic field in the region RA can be mainly applied to the magnetic sensor unit 3a by setting the uniformity u to 0.6 or more. The inclusion of the structure in which the uniformity u is 0.6 or more can improve the uniformity of the intensity Bas of the calibration magnetic field applied to the magnetic sensor unit 3 a.

According to the semiconductor device of the present embodiment, the distance in the horizontal direction between the excitation wiring 24 and the magnetic sensor unit 3a can be reduced, and therefore the magnetic field generation efficiency is high. Further, according to the semiconductor device of the present embodiment, since the excitation wire 24 can be disposed at a position close to the center in the width direction of the magnetic sensor unit 3a, the excitation wire 24 can be separated from the peripheral circuit, and the thermal influence of heat generated by the excitation wire 24 on the peripheral circuit can be reduced. Therefore, according to the semiconductor device of the present embodiment, it is possible to suppress characteristic variations due to heat of the peripheral circuit, such as an asymmetric temperature distribution occurring in the peripheral circuit. Therefore, according to the semiconductor device of the present embodiment, the sensing sensitivity of the vertical hall element 3 can be estimated with high accuracy.

Although the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the specific embodiments. For example, the materials, dimensions, and the like shown in the above description are only examples, and are not limited thereto.

In the above embodiment, the configuration of the semiconductor devices 1A and 1B in which the excitation wirings 4 and 24 are arranged in a partial region directly above the magnetic sensor unit 3a in the width direction has been described, but the semiconductor devices 1A and 1B are not limited to this example. In the semiconductor device 1A, the excitation wiring 4 may be disposed so as to overlap at least a part of the width of the magnetic sensor section 3a or may be disposed so as to overlap the entire magnetic sensor section 3a in a plan view in the depth direction. In the semiconductor device 1B, the excitation wiring 24 may be disposed so as to overlap at least a part of the width of the magnetic sensor section 3a or may be disposed so as to overlap the entire magnetic sensor section 3a in a plan view in the depth direction.

From the viewpoint of improving the uniformity u, it is preferable that the semiconductor devices 1A and 1B have the excitation wires 4 and 24 arranged so as to overlap with the entire width of the magnetic sensor section 3a, as compared with the semiconductor devices 1A and 1B having the excitation wires 4 and 24 arranged so as to overlap with a part of the width of the magnetic sensor section 3a in the plan view.

In the above embodiment, the excitation wiring 4 formed linearly has been described, but the excitation wiring 4 is not necessarily formed linearly in the entire longitudinal direction. The excitation wiring 4 may be formed linearly at least in a portion overlapping with the magnetic sensor portion 3a in a plan view of the front surface S, and the other portion is not necessarily formed linearly.

In the above embodiment, the case where the 1 st distance and the 2 nd distance are equal (fig. 4 (a)) and the case where the 1 st distance is smaller than the 2 nd distance (fig. 4 (b)), that is, the case where the 1 st distance is equal to or smaller than the 2 nd distance (fig. 4) are described. In addition, as an example of the case where the 1 st distance is smaller than the 2 nd distance, the semiconductor device 1B including the excitation wiring 24, in which the excitation wiring 24 is disposed at a position where the distance from the width direction center of the magnetic sensor section 3a to the end surface 24R is shorter than the distance from the width direction center of the magnetic sensor section 3a to the end surface 24L, has been described. However, the present invention is not limited to this example. In the semiconductor device 1B, the excitation wiring 24 may be arranged so that the distance from the width direction center of the magnetic sensor section 3a to the end face 24L is shorter than the distance from the width direction center of the magnetic sensor section 3a to the end face 24R.

When the excitation wiring 24 is disposed such that the distance from the width direction center of the magnetic sensor section 3a to the end face 24L is shorter than the distance from the width direction center of the magnetic sensor section 3a to the end face 24R, the distance from the width direction center of the magnetic sensor section 3a to the end face 24L is the 1 st distance and the distance to the end face 24R is the 2 nd distance in plan view in the depth direction. The distance Wc/2 corresponds to the distance from the center of the magnetic sensor unit 3a in the width direction to the end surface 24L.

The above embodiments can be implemented in various ways, and various modifications such as omission and replacement can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope and equivalents of the invention described in the claims.

[ Mark Specification ]

1A, 1B semiconductor devices; 2 a semiconductor substrate; 3a vertical hall element; 3a magnetic sensor; 4. 24 excitation wiring; 6a, 6b insulating layers; 7 electrodes; 8 diffusion layer.