JP3260495B2 - Semiconductor device for optical position detection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical position detecting semiconductor device for converting the position of incident light into an electric signal, and in particular, used in combination with a light emitting element for measuring the position of an object and the distance to the object. And a light position detecting semiconductor device for detecting two-dimensional position coordinates on a light receiving surface.

[0002]

2. Description of the Related Art Conventionally, a semiconductor device of this kind for two-dimensional light position detection (two-dimensional PSD (Position Sens.
active detector)) as shown in FIG.

In FIG. 4 (A) and FIG. 4 (B), which is a cross-sectional view taken along line AA of FIG. 4 (A), a semiconductor device for optical position detection has a rectangular shape on the surface of an n-type semiconductor substrate 101. Shape p
A diffusion layer 102 is formed, and a pair of electrodes 103 and 104 electrically connected to the p-type diffusion layer 102 are formed along two opposing sides of the p-type diffusion layer 102. A pair of electrodes 105 and 106 are formed on the back surface of the substrate 101 in parallel to the other two sides of the p-type diffusion layer 102 so as to be orthogonal to the 104, and an electric signal in the x direction is extracted from the electrodes 103 and 104. , And extract electric signals in the y direction from the electrodes 105 and 106.

In such a configuration, the position signal current in the y direction is applied to the two electrodes 1 formed on the back surface of the semiconductor substrate 101.
05, 106, when mounting the chip on the package, a special way to prevent conduction between the semiconductor substrate and the conductive part of the package other than the electrodes or other than the electrodes. Care was needed.
Further, since the electrodes 103 and 104 and the electrodes 105 and 106 are formed on the front surface and the back surface of the semiconductor substrate 101,
Production was troublesome. Further, the electrodes 103 and 10
Since the electrode 4 and the electrodes 105 and 106 are formed on the front surface and the back surface of the semiconductor substrate 101, accurate relative positioning of the respective electrodes becomes difficult, and there is a case where the detection accuracy is reduced due to the relative position shift. .

[0005]

As described above,
In the conventional semiconductor device for optical position detection shown in FIG.
Since the electrodes for extracting the position signal current obtained according to the incident light were formed on the front and back surfaces of the semiconductor substrate, it took time and effort to form and position the electrodes,
Special considerations were required for mounting. For this reason,
This has led to a decrease in manufacturing efficiency.

Accordingly, the present invention has been made in view of the above, and an object of the present invention is to form all electrodes for extracting position detection signals on the surface of a semiconductor substrate to improve detection accuracy and manufacture. It is an object of the present invention to provide a light-position detecting semiconductor device which facilitates the above.

Another object of the present invention is to provide a light position detecting semiconductor device which simplifies signal processing without deteriorating the linearity of a position detection signal.

[0008]

In order to achieve the above-mentioned object, a first means for solving the problem is a rectangular semiconductor of a second conductivity type formed on a surface of a semiconductor substrate of the first conductivity type. A pair of diffusion layers of the first conductivity type formed so as to reach from the surface of the semiconductor layer to the semiconductor substrate in parallel with the two opposite sides of the semiconductor layer; Formed first and electrically connected to the respective diffusion layers.
And a second pair of electrodes formed parallel to the other two opposite sides of the semiconductor layer so as to be orthogonal to the first pair of electrodes and electrically connected to the semiconductor layer. And an electrode.

[0009]

[0010] A second means for solving the problem is a rectangular first conductive type first semiconductor substrate formed on a first conductive type semiconductor substrate.
Semiconductor layer, a first conductive type second semiconductor layer formed on the semiconductor substrate or the first semiconductor layer, and a rectangular second conductive type third semiconductor layer formed on the second semiconductor layer. And a pair of diffusion layers of the second conductivity type formed from the surface of the second semiconductor layer to reach the first semiconductor layer in parallel with two opposing sides of the first semiconductor layer. And a first pair of electrodes formed along the respective diffusion layers and electrically connected to the diffusion layers, respectively, and a third semiconductor layer orthogonal to the first pair of electrodes. A second pair of electrodes formed in parallel with the two opposing sides and electrically connected to the third semiconductor layer; and a second pair of electrodes formed so as to reach the semiconductor substrate from the surface of the second semiconductor layer. It is composed of a diffusion layer of one conductivity type and a third electrode electrically connected to the diffusion layer of first conductivity type.

[0011]

According to the present invention, an electrode for extracting position detection signals in the x and y directions is formed on the surface of the semiconductor substrate.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing a structure of a semiconductor device for detecting a light position according to an embodiment of the present invention, and FIG.
FIG. 1B is a plan view, FIG. 1B is a cross-sectional view along line AA in FIG. 1A, and FIG. 1C is a cross-sectional view along line BB in FIG. 1A. is there.

In FIG. 1, a p-type rectangular diffusion layer 2 is formed on an n-type silicon substrate 1. In the diffusion layer 2, a pair of diffusion layers 3, 4 having a depth reaching the substrate 1 from the surface of the diffusion layer 2 is formed in parallel with one of two opposite sides of the diffusion layer 2. A pair of cathode electrodes 5 and 6 made of aluminum are formed on the pair of diffusion layers 3 and 4, respectively. The cathode electrodes 5 and 6 are connected to the substrate 1 via the diffusion layers 3 and 4 respectively. Is electrically connected to

On the diffusion layer 2, a cathode electrode 5,
A pair of anode electrodes 7 and 8 made of aluminum are formed in parallel with the other two opposite sides of the diffusion layer 2 so as to be perpendicular to the diffusion layer 2. Is electrically connected to The position signal current in the x direction with respect to the incident light is obtained from the cathode electrodes 5 and 6, and the position signal current in the y direction with respect to the incident light is obtained in the anode electrodes 7 and 8.
Respectively.

In such a structure, it is not necessary to form an electrode for extracting the position signal current on the back surface of the semiconductor substrate, and all electrodes for extracting the position signal current may be formed on the surface of the semiconductor substrate. Manufacturing is simplified. Further, since the electrode for extracting the position signal current is not formed on the back surface of the semiconductor substrate, it is not necessary to perform complicated positioning when mounting the chip on the frame, and mounting can be performed easily. . Further, unlike the related art, it is not necessary to perform the relative alignment between the electrodes formed on the front surface and the back surface of the substrate, which simplifies the manufacturing and improves the detection accuracy.

For these reasons, the above-described structure is suitable for mass production, and can improve productivity. It is also extremely advantageous in promoting monolithic operation including this device and a processing circuit for processing a signal obtained from this device.

FIGS. 2A and 2B are views showing the structure of a semiconductor device for detecting a light position according to another embodiment of the present invention. FIG. 2A is a plan view, and FIG. A-A)
It is sectional drawing which follows the A line | wire, The figure (C) is B of the figure (A).
It is sectional drawing which follows the -B line.

In FIG. 2, a p-type buried diffusion layer 12 is formed on an n-type silicon substrate 11. On this buried diffusion layer 12, an n-type silicon layer 13 is formed by an epitaxial growth method. The silicon layer 13 includes a pair of p-type diffusion layers 15 and 16 having a depth reaching the buried diffusion layer 12 from the surface of the silicon layer 13.
The buried diffusion layer 12 is formed in parallel with two opposing sides. Further, a p-type diffusion layer 14 is formed on the surface of the silicon layer 13.

A pair of anode electrodes 19 and 20 made of aluminum are formed on the pair of diffusion layers 15 and 16, respectively.
It is electrically connected to the buried diffusion layer 12 via 16. An anode electrode 1 is formed on the p-type diffusion layer 14.
A pair of anode electrodes 17 and 18 made of aluminum are formed in parallel with two opposing sides of the buried diffusion layer 14 so as to be orthogonal to 9 and 20.
Reference numeral 18 is electrically connected to the buried diffusion layer 14.
On the back surface of the semiconductor substrate 11, a cathode electrode 21 is formed. The position signal current in the x direction with respect to the incident light is obtained from the anode electrodes 17 and 18, and the position signal current in the y direction with respect to the incident light is obtained in the anode electrodes 19 and 2.
0 respectively.

In such a structure, the detection layers for detecting the positions of the light spots in the x and y directions with respect to the incident light are made independent of the buried diffusion layer 12 and the diffusion layer 14 on the surface. It is possible to suppress deterioration of signal linearity due to the influence between the electrodes when four electrodes are extracted from one diffusion layer.

Further, since it is formed of the same conductivity type as the buried diffusion layer 12 serving as a detection layer for detecting the positions of light spots in the x and y directions with respect to the incident light and the diffusion layer 14 on the surface,
The position signals in each direction can be handled in exactly the same way, and the signal polarity is not reversed by extracting the position detection signals with the different conductivity type detection layers as in the past, and the signal processing is performed. Easy to do.

Further, since only one electrode is formed on the back surface of the semiconductor substrate 11, the above-described special consideration is not required when mounting the chip on the frame.

FIGS. 3A and 3B are views showing the structure of a semiconductor device for detecting a light position according to another embodiment of the present invention. FIG. 3A is a plan view, and FIG. A-A)
It is sectional drawing which follows the A line.

The features of the embodiment shown in FIG. 3 are as follows.
In the embodiment shown in FIG. 2, an n-type diffusion layer 31 reaching the substrate 11 from the silicon layer 13 is provided on the n-type silicon layer 13 instead of the cathode electrode 21 formed on the back surface of the semiconductor substrate 11. A cathode electrode 32 is formed on the diffusion layer 31.
Is formed, and the cathode electrode 32 is connected to the anode electrodes 17 and 1.
It is provided on the surface of the semiconductor substrate 11 similarly to 8, 19, and 20.

In such a structure, both the effects obtained in the embodiments shown in FIGS. 1 and 2 can be obtained.

Note that the present invention is not limited to the above embodiment, and a semiconductor material other than silicon may be used, and the conductivity type may be reversed.

[0028]

As described above, according to the present invention, the electrodes for extracting the position detection signals in the x and y directions are formed on the surface of the semiconductor substrate, so that the manufacturing is simplified and the production is simplified. And the detection accuracy can be improved.

Further, according to the present invention, since the detection layers for detecting the position detection signals in the x direction and the y direction are made independent and of the same conductivity type, the linearity of the position detection signals deteriorates. Can be avoided, and signal processing can be simplified.

[Brief description of the drawings]

FIG. 1 is a view showing a structure of a semiconductor device for detecting a light position according to an embodiment of the present invention.

FIG. 2 is a diagram showing a structure of a semiconductor device for detecting a light position according to another embodiment of the present invention.

FIG. 3 is a diagram showing a structure of a semiconductor device for detecting a light position according to another embodiment of the present invention.

FIG. 4 is a view showing a structure of a conventional semiconductor device for detecting a light position.

[Explanation of symbols]

 1,11 semiconductor substrate 2,12,14,15,16 p-type diffusion layer 3,4,31 n-type diffusion layer 5,6,21,32 cathode electrode 7,8,17,18,19,20 Negative electrode 13 n-type silicon layer

Continuation of front page (56) References JP-A-4-256377 (JP, A) JP-A-4-10581 (JP, A) JP-A-63-117203 (JP, A) JP-A-2-246168 (JP) , A) (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 31/16-31/173

Claims (2)

(57) [Claims] A first conductive type semiconductor layer formed on a surface of the first conductive type semiconductor substrate; and a rectangular second conductive type semiconductor layer formed on a surface of the semiconductor layer in parallel with one of two opposing sides of the semiconductor layer. A pair of first conductivity type diffusion layers formed so as to reach the semiconductor substrate; a first pair of electrodes formed along the respective diffusion layers and electrically connected to the respective diffusion layers; A second pair of electrodes formed parallel to the other two sides of the semiconductor layer so as to be orthogonal to the first pair of electrodes and electrically connected to the semiconductor layer. A semiconductor device for detecting a light position. 2. A first semiconductor layer of a rectangular second conductivity type formed on a semiconductor substrate of the first conductivity type, and a first conductivity type of a first conductivity type formed on the semiconductor substrate or the first semiconductor layer. A second semiconductor layer, a rectangular second semiconductor layer of the second conductivity type formed on the second semiconductor layer, and a second semiconductor layer in parallel with two opposing sides of the first semiconductor layer. A pair of second conductivity type diffusion layers formed so as to reach the first semiconductor layer from the surface of the semiconductor layer; and a pair of diffusion layers formed along the respective diffusion layers and electrically connected to the respective diffusion layers. The first pair of electrodes are formed in parallel with two opposing sides of the third semiconductor layer so as to be orthogonal to the first pair of electrodes, and are electrically connected to the third semiconductor layer. A second pair of electrodes, a first conductivity type diffusion layer formed to reach the semiconductor substrate from the surface of the second semiconductor layer; Conductivity type diffusion layer and the light position detecting semiconductor device and having a third electrode electrically connected.