JP2972303B2 - 2D optical position detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a light-receiving portion of a first-conductivity-type semiconductor substrate, which is doped with a second-conductivity-type impurity to form a resistance portion, and the light-receiving portion is covered with the impurity. The present invention relates to a two-dimensional optical position detector that detects a position of a light spot in the light receiving unit based on a photocurrent that has passed through the resistance unit when light from a measurement object is incident as a light spot.

[Prior Art] FIG. 4 is a perspective view showing a conventional two-dimensional optical position detector. FIG. 3A shows a rectangular P-shaped surface of the N-type semiconductor substrate 1.
The light receiving portion 2 is formed by doping a mold impurity.
The signal extraction electrode 3 is attached to each end side.

In FIG. 1B, a light-receiving portion 2 is formed by doping a surface of an N-type semiconductor substrate 1 with a P-type impurity in a rectangular shape, and a signal extraction electrode 3 is attached to an opposite end of the light-receiving portion 2. Further, the rear surface of the N-type semiconductor substrate 1 is doped with N-type impurities in a rectangular shape, and the signal extraction electrodes 4 are arranged in a direction orthogonal to the signal extraction electrodes 3 attached to the front surface.

FIG. 2C shows a diamond-shaped light receiving portion 5 formed by doping a diamond-shaped P-type impurity on the surface of the N-type semiconductor substrate 1, and a P-type wire resistance portion 6 along each side of the diamond-shaped light receiving portion 5. The signal extraction electrode 7 is attached to each intersection of the P-type wire resistance section 6.

FIG. 3D shows a case where an N-type epitaxial growth layer 9 is formed on a P-type semiconductor substrate 8 and a light-receiving portion 10 is formed by doping a surface of the epitaxial growth layer 9 with a P-type impurity in a rectangular shape. Signal extraction electrodes on opposite sides inside 10
11 and attach the light receiving section 10 in the direction
The signal extraction electrode 12 is attached to the opposite end outside the device (JP-A-1-276778).

[Problems to be solved by the invention]

However, in the two-dimensional optical position detector shown in FIG. 2A, the electric field formed in the light receiving section 2 is directed to the signal extraction electrodes 3 in four directions. There is a disadvantage that a difference occurs in the moving speed of the generated charges depending on the incident position, and the position detection error becomes extremely large.

According to the two-dimensional optical position detector shown in FIG. 2B, the electric field in the light receiving section 2 is uniform, but the operating layers as position detecting elements exist on both sides of the N-type semiconductor substrate 1. ,
The fabrication of the device is difficult. Further, there is a problem that the resistance between the signal extraction electrodes 4 cannot be increased.

Further, according to the two-dimensional optical position detector shown in FIG. 3C, the surface resistance of the rhombus-shaped light receiving section 5 and the P-type wire resistance section 6 have to be in a fixed relationship with high accuracy, and high-precision manufacturing is required. It is. Further, there is a problem that the resistance between the signal extraction electrodes 7 cannot be increased.

Further, in the two-dimensional optical position detector shown in FIG. 3D, the resistance of the epitaxial growth layer 9 becomes the resistance between the signal extraction electrodes 12, so that the variation becomes large, and the resistance between the electrodes may become too large. There is a problem that can not be.

Therefore, an object of the present invention is to provide a two-dimensional optical position detector that can reduce the position detection error and increase the resistance between the electrodes.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a semiconductor layer formed by doping a surface of a light receiving portion of a first conductivity type (eg, N type) semiconductor substrate with a second conductivity type (eg, P type) impurity. A two-dimensional optical position detector that detects the position of a light spot in a light receiving unit based on a photocurrent that has passed through the semiconductor layer when light from the device under test is incident as a light spot,
The semiconductor layer is configured to include at least a plurality of first resistance units arranged at predetermined intervals in a certain direction (for example, the X direction) and a plurality of conductive units arranged between the first resistance units; Further, a pair of first signal extraction electrodes commonly connected to both ends of the plurality of first resistance portions, a second resistance portion in which the conductive portions are connected in proportion to an arrangement interval, and a second resistance portion; And a pair of second signal extraction electrodes connected to both ends of the unit.

[Action]

Since the present invention is configured as described above, the photocurrent generated by the light incident on the light receiving unit passes through the first resistance unit at a distance (resistance value) determined by the incident position, and then a pair of first currents. It is divided and output from the signal extraction electrode. Here, the first resistance portion extends in a fixed direction, and the photocurrent passes through the resistance portion at a predetermined distance according to the incident position of the light spot. Therefore, the photocurrent is inversely proportional to the resistance value to the signal extraction electrode. Is divided. Therefore, for example, the position of the light spot in the X direction can be specified by a known calculation based on the current extracted from the signal extraction electrode.

Similarly, the light incident on the light receiving portion is collected by the conductive portion extending in a certain direction, and after passing through the second resistor portion at a distance (resistance value) determined by the incident position as a photocurrent, a pair of second light is transmitted.
It is divided and output from the signal extraction electrode. Therefore, for example, the position of the light spot in the Y direction can be specified by a known calculation based on the current value output from the second signal extraction electrode.

Therefore, since the incident position of the light spot is specified in the X direction and the Y direction, the two-dimensional position of the light spot on the light receiving unit is specified.

〔Example〕

Hereinafter, a two-dimensional optical position detector according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the description, the same elements will be denoted by the same reference symbols, without redundant description.

FIG. 1 is a perspective view showing a two-dimensional optical position detector using a comb-shaped striped pattern and a striped striped pattern, and FIG. 2 is a plan view (FIG. 1A) and a partial cross-sectional view showing a cross-sectional structure. ((B), (c), (d) in the same figure). Here, FIG. 2B is a sectional view taken along line AA ′, FIG. 2C is a sectional view taken along line BB ′, and FIG. 2D is a sectional view taken along line CC ′.

This two-dimensional optical position detector is constituted by combining a comb-shaped striped pattern 13 and a striped striped pattern 14 as shown in FIG. The comb-shaped striped pattern 13 includes a P-type branch conductive portion 13c serving as a comb portion, a P-type main resistance portion 13r connected to one end thereof, and a signal extraction electrode connected to both ends of the P-type main resistance portion 13r. 13e. As shown in FIG. 2 (b), the P-type branch conductive portion 13c is formed at a predetermined interval inside the N-type semiconductor substrate 1, and is formed on the surface of the P-type branch conductive portion 13c and the surface of the N-type semiconductor substrate 1. Has an insulating film 15 formed thereon. Since the insulating film 15 is formed of a transparent material such as a semiconductor oxide film, the incidence of light on the N-type semiconductor substrate 1 is not hindered. Therefore, from the signal extraction electrode 13e, a photocurrent corresponding to the light incident position is divided and output from each electrode, and based on these output values,
The position of the light in the X direction can be specified. In addition, P-type core resistance part
Since the ratio of the length and width of 13r can be set to about 100 or more, the resistance between the electrodes can be increased.

On the other hand, the stripe-shaped striped pattern 14 is composed of a pair of signal extraction electrodes 14e such as Al extending in the X direction and a plurality of P-type resistance portions 14r arranged in a stripe between the signal extraction electrodes 14e. ing. As shown in FIG. 2 (d), the P-type resistance portions 14r are formed inside the N-type semiconductor substrate 1 at predetermined intervals between the P-type branch conductive portions 13c. The above-described P-type branch conductive portion 13c and P-type resistance portion 14r can be formed by doping a P-type impurity. The signal extraction electrode 14e is formed of Al or the like on the insulating film 15,
As shown in FIG. 2 (c), since it is connected to the P-type resistance portion 14r through the contact hole 15h, it is possible to generate a leak current between the P-type branch conductive portion 13c and the signal extraction electrode 14e. There is no. The light that has entered the light receiving portion as a light spot becomes a photocurrent, flows through the P-type resistor portion 14r, and is divided and output from the signal extraction electrode 14e. Since the distance that the photocurrent passes through the P-type resistor portion 14r varies depending on the incident position of the light, the position of the light in the Y direction is specified based on these output values. The ratio between the length and the width of the P-type resistor 14r can be set to about 5 or more.

Since this embodiment is configured as described above, the coordinate position in the X direction can be specified by the current value divided and output from the signal extraction electrode 13e via the P-type main resistor 13r. The coordinate position in the Y direction can be specified by the current value divided and output from the signal extraction electrode 14e via the P-type resistor 14r. Therefore, the incident position of the light spot on the light receiving section can be specified in a planar manner by these current values.

Note that a signal processing circuit for processing a signal current obtained from these electrodes is publicly known, and thus description thereof is omitted.

Next, based on FIG. 3, a second embodiment according to another embodiment of the present invention will be described.
The three-dimensional light position detector will be described. FIG. 4A shows a crank-shaped pattern 16 in the stripe-shaped striped pattern 14 shown in FIG.
(Including 16e and 16r).
The crank-shaped pattern 16 includes a resistor portion 16r formed of a uniform semiconductor layer extending continuously in the X direction and the Y direction in a crank shape, and a pair of signal extraction electrodes 16e connected to both ends of the resistor portion 16r. The resistance portion 16r extending continuously in the X direction and the Y direction is configured to include a plurality of divided resistance pieces extending in the X direction, and the plurality of divided resistance pieces are alternately formed with conductive portions (resistances). (A portion extending in the Y direction of the resistance portion 16r disposed between the portions 14r) to form a crank shape as a whole. In other words, the resistor 14r of the striped stripe pattern 14 is
A plurality of conductive parts (Y of the resistance part 16r) forming a part of the resistance part 16r.
(A part extending in the direction).

The resistance part 14r and the resistance part 16r are formed by doping a N-type semiconductor substrate with a P-type impurity. After forming the resistance part 14r and the resistance part 16r, the surface is covered with an insulating film, and the signal extraction electrodes 14e and 16e are formed on the surface. As described above, the signal extraction electrodes 14e and 16e are connected to the resistance portions 14r and 16r via the contact holes.

The plane coordinate position of the light spot incident on the light receiving portion is determined by the resistance portion 14r arranged in the X direction and the resistance portion 1 extending in the Y direction.
The photocurrent passing through each 6r is applied to each signal extraction electrode.
It can be specified by a known calculation based on the output values divided and output from 14e and 16e.

FIG. 4B shows a combination of the comb-shaped striped pattern 13 shown in FIG. 1 with a modified striped pattern 17 (including 17e and 17r). The deformed stripe pattern 17 includes a crank-shaped resistor 17r obtained by deforming the resistor 14r shown in FIG. 1 into a crank shape. This crank type resistance part 17r
Are formed of a continuous and uniform semiconductor layer, and are arranged between the conductive portions 13c of the comb-shaped striped pattern 13. Here, the resistance part 13r, the conductive part 13c, and the crank type resistance part 17r
Are formed by doping a p-type impurity on an n-type semiconductor substrate, and the signal extraction electrodes 13e and 17e are connected to the resistor 13r and the crank-shaped resistor 17r via the contact holes, respectively, as described above. Have been.

The plane coordinate position of the light spot incident on the light receiving portion is an output value obtained by dividing the photocurrent passing through the basic resistor portion 13r extending in the X direction and the crank-shaped resistor portion 17r arranged in the Y direction from the respective electrodes. Can be specified by a known calculation based on

Here, in FIGS. 9A and 9B, the crank-shaped resistance portions 16r and 17r are formed of uniform resistors, but one of the Y-direction component and the X-direction component is provided. You may comprise a high resistance body and the other by a low resistance body.

FIG. 3C shows a fan-shaped stripe pattern 18 (18e, 18r).
) And a fan-shaped comb-shaped pattern 19 (including 19c, 19e, and 19r). In the fan-shaped stripe pattern 18, a plurality of resistance portions 18r are connected in the radial direction to signal extraction electrodes 18e arranged in a double circle. Further, the fan-shaped comb-shaped pattern 19 includes a plurality of current-collecting conductive portions 19c extending radially on the resistor portion 19r arranged in the circumferential direction.
Is connected. In this case, the position of the light spot incident on the light receiving unit is specified by the output value divided and output from each signal extraction electrode 18e, 19e after passing through the resistance units 18r, 19r arranged in the radial direction and the circumferential direction. Can be.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made. For example, as the striped pattern, a plurality of resistance portions 14r arranged between the conductive portions 13c shown in FIG. 1 may be used instead of one.

In the above embodiment, the optical position detector is formed on the N-type semiconductor substrate. However, on the N ⁺ -type epitaxial layer formed by depositing N-type impurities at a high concentration on the surface of the N-type semiconductor substrate. It may be formed.

Further, in the above embodiment, an impurity layer doped with a P-type impurity is used as the P-type main resistor. However, a P-type impurity is used as the semiconductor substrate, and the impurity is N-type or a high-resistance metal thin film is used as the P-type main resistor. May be used.

〔The invention's effect〕

Since the present invention is configured as described above, the electric field between the electrodes becomes uniform, and the position detection error in the two-dimensional optical position detector can be reduced.

Further, since the resistance between the electrodes can be increased, the spot position can be detected even when the amount of incident light is small.

Furthermore, since the X and Y directions are independent of each other,
Connection with the arithmetic circuit system is easy.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the configuration of a two-dimensional optical position detector according to one embodiment of the present invention, and FIG. 2 is a comb-like stripe pattern and a stripe-like stripe pattern formed on the semiconductor substrate shown in FIG. FIG. 3 is a plan view showing an example of a cross-sectional structure of a pattern, FIG. 3 is a plan view showing a pattern example of a resistive portion and a conductive portion of a two-dimensional optical position detector according to another embodiment of the present invention, and FIG. 1 is a perspective view showing a configuration of a two-dimensional optical position detector according to the first embodiment. 1... N-type semiconductor substrate, 2, 10.
7, 11, 12 ... signal extraction electrode, 5 ... diamond-shaped light receiving section, 6 ...
... P-type wire resistance section, 8 ... P-type semiconductor substrate, 9 ... N-type epitaxial growth layer, 13 ... comb stripe pattern, 14 ...
Striped striped pattern, 15 ... insulating film, 16 ... crank-shaped pattern, 17 ... deformed striped pattern, 18
... fan-shaped stripe pattern, 19 ... fan-shaped comb pattern.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yukio Inose 1126 Nomachi, Hamamatsu-shi, Shizuoka Pref. Hamamatsu Photonics Co., Ltd. JP-A-289876 (JP, A) JP-A-1-101672 (JP, A) JP-A-1-115169 (JP, A) JP-A-1-115170 (JP, A) (58) Fields investigated (Int. . ^6, DB name) H01L 31/16

Claims (3)

(57) [Claims] A semiconductor layer is formed by doping a surface of a light receiving portion of a semiconductor substrate of a first conductivity type with an impurity of a second conductivity type, based on a photocurrent when light enters the light receiving portion as a light spot. A two-dimensional optical position detector for detecting a position of a light spot in the light receiving unit, wherein the semiconductor layer is disposed between a plurality of first resistance units arranged at predetermined intervals in a certain direction and the first resistance unit; And a pair of first signal extraction electrodes commonly connected to both ends of the plurality of first resistance portions, and a plurality of the conductive portions are arranged at intervals. And a pair of second signal extraction electrodes connected to both ends of the second resistance portion. 2. The semiconductor device according to claim 1, wherein said second resistance section includes a plurality of division resistance pieces, and said division resistance pieces are alternately connected to said conductive section to form a crank shape. Item 2. The two-dimensional light position detector according to Item 1. 3. The two-dimensional optical position detector according to claim 2, wherein said dividing resistor piece and said conductive part are formed of the same semiconductor layer.