JPS58188968A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To improve integration density and to obtain a solid-state image pickup device with high resolution, by arranging a photodetecting element equipped with a photoelectric converter on one main surface of a semiconductor substrate, and arranging a circuit element for processing a signal from the photodetecting element on the other main surface. CONSTITUTION:The photodetection part is formed of an (n) type impurity layer 11 by thermal diffusion, etc., on the surface layer part of one main surface 10a of a (p) type Si substrate 10 and the impurity layer 11 is surrounded with a charge barrier 12 made of a (p) type impurity layer with high density. Further, a signal processing circuit element having a transfer gate TG and transfer electrodes phi1-phi4 is formed on the other main surface 12b through an SiO2 film 13. An output terminal by a depth-directional recessed part 14 and the input terminal 15 of the signal processing circuit element are formed of (n) type diffused layers 16 with high density at the peak part of the photodetection part while piercing both main surfaces 10a and 10b. Then, a solid-state image pickup device with a matrix array is formed on the semiconductor substrate 20 and coupled with the signal processing circuit through an (n) type diffused layer 22 without forming the signal processing circuit on the array of photodetecting elements 21, improving the degree of integration.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a one-dimensional or two-dimensional solid-state imaging device, and particularly relates to a light-receiving element that is sensitive to incident light and a signal charge that is photoelectrically converted by the light-receiving element. The present invention relates to the structure of a solid-state imaging device including circuit elements for processing.

(b) Background of the Technology In recent years, research and development has been carried out to increase the degree of integration in order to realize a high-resolution solid-state imaging device by increasing the number of light-receiving elements.

+(3+ Prior Art and Intermediate Points Figure 1 is a conceptual L-plane diagram for explaining a conventional solid-state imaging device. Here, a two-dimensional solid-state imaging device using an f&8×8 ink fin transfer method is shown as an example. ing.

In FIG.
are arranged in a matrix, and a transfer register (TO) and a vertical shift register VS are arranged corresponding to each light receiving element 2 arranged in each column. Further, a horizontal shift register f(S) and an output amplifier AMP are provided for outputting signal charges from each vertical shift register vS in time series.

In such a solid-state imaging device, light incident on the light-receiving element 2 is converted into light tge within the light-receiving element to generate signal charges. The signal charge is temporarily accumulated within the light receiving element. When the transfer gate TG is opened, the signal charges accumulated for a certain period of time are transferred to the vertical shift register vS, and after sequentially transferred within the vertical shift register VS, the signal charges are transferred to the horizontal shift register E.
(Moves to S in parallel) Further, the signal charge is transported within the horizontal shift register H8 and output amplification 1 (l A M
It is converted into voltage at P and read out in time series. Note that the first
Arrows in the figure indicate the flow of the signal charges.

In the solid-state imaging device configured as described above, each light receiving element 2 has a transfer gate TO, a vertical 1 [same as a signal processing circuit element such as a shift lens VS and a horizontal shift lens H8].
Since it is configured as a substrate ball, the ratio of the effective light-receiving area within the substrate 1 is reduced, and the resolution is hindered.

(■ Purpose of the Invention In view of the drawbacks of the conventional technology, the present invention dramatically improves the integrated IF by effectively utilizing both principal surfaces of a semi-quadram resistor, thereby providing a high-resolution solid-state imaging device. The purpose is to

+611 Structure and object of the invention According to the present invention, a light-receiving element, which is a photoelectric conversion element, is arranged on one main surface of a semi-quartet board, and a signal charge from the light-receiving element is transmitted to the north side of the pond. A circuit element for processing is arranged, and the signal vi1. By providing a solid-state imaging device characterized in that a conductive 111c type impurity layer is provided through the substrate for electrical connection with the input end through which a charge is introduced. Can be done.

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

FIG. 2 is a schematic diagram showing the configuration of a solid-state imaging device including one light-receiving element according to the present invention.
+ is a plan view of the light receiving element and signal processing circuit element formed on each side of the substrate, and Figure 2 (to) is a cross section of Figure 2 μ) and tc + -x', Y-Y'. FIG.

In the figure, IO is a semiconductor substrate made of, for example, a p-type S1 wafer, and a light-receiving layer made of an n-type impurity layer formed by ion implantation or thermal diffusion on a part of the main surface tOa of the substrate IO. A portion 11 is formed, and the periphery of the light-receiving portion is surrounded by a weir 12 made of a highly concentrated p-type impurity.On the other hand, a tab on one main surface of the substrate 10 is coated with, for example, S1 oxide. @(S1υ1I) Transfer via 18) TG and the transfer electrodes of the charge coupled device, which becomes the vertical shift register, DA1, DA2, 43, 4, etc. are arranged to form the circuit elements of the signal processing circuit. Then, the light receiving section 2 output end 1
4 and the input end 15 of the signal processing circuit element wL, a high concentration n-type impurity layer 16 which is an impurity layer of the type that conducts with the substrate 10 is formed on both main surfaces toa of the substrate 10.
It is formed to pass through the tab.

Thus, using the configuration e as described above, for example 8X
8) If you create a solid-state imaging device with an IJ Tsuknu array, it will look like the one shown in Figure 8. As is clear from this figure, since the signal processing circuit element is not on the surface on which the light receiving element 21 is disposed, the light receiving element 21 can be placed close to each other, and the degree of integration can be dramatically increased. In FIG. 8, 20 is a semiconductor substrate, and 22 is an impurity layer of a conductivity type opposite to that of the substrate 20, which electrically connects the light receiving element 21 and a signal processing circuit element disposed on one main surface of a pond (not shown). It has the role of connecting people.

Next, the operation of the solid-state imaging device of the present invention will be explained using FIG. 2.

When the incident light 17 enters the light receiving section 11, signal charges (electrons in this case) generated by photoelectric conversion in the light receiving section are transferred to a potential well 18 under the light receiving section 11 and the n-type impurity layer 16.
is temporarily accumulated. When the transfer gate (TG) is opened, the signal charge accumulated for a certain period of time is transferred to the potential well 19 of the transfer electrode summer 1F of the charge transfer device through the transfer gate (TG). Furthermore, the transfer electrode 01 of the charge transfer device. g, as
, when the driving signals are sequentially applied to D4, the load is transferred in the direction of the arrow +01 in FIG. 2, and then transferred to the horizontal shift register (not shown in FIG. 25); The voltage is transferred to the output amplifier, where it is converted to voltage and output.

Note that impurity # for electrically connecting the output terminal 14 of the light receiving element 11 and the input @ 15 of the signal processing circuit element described above
An example of forming the device 16 will be described with reference to FIG.

Normally, the thickness of the semiconductor substrate 80 is about 800 μm,
The substrate 80 is chemically polished leaving a width l of 5 sm at the periphery of the surface 80a, and the thickness dl at the center of the substrate is reduced to about 20 μm. Furthermore, recesses 81 are provided at predetermined positions using a technique such as anisotropic etching, and the four portions 81 are
The distance jlidl between the bottom of the pond and one main surface 80b of the pond is 577
Make it about m. Thereafter, by diffusing impurities of a conductivity type opposite to that of the substrate 80 to a depth of 6 μm or more, a diffusion N182 penetrating the newly formed main surface 800 and the curved main surface 80b is easily formed in the substrate. can do.

Incidentally, the reason why the radius around the semiconductor substrate 80 is kept as thick as about 6W at the initial thickness is to facilitate handling of the wafer.

If anisotropic etching is employed to form the recess 81 as described above, a square heel-shaped recess can be formed. In this case, the (100)-plane Si substrate BO is used, and after masking the area other than the area where the square heel-shaped four parts are to be formed with photoresist, a mixed aqueous solution of HBO (water) and N5k14 (hydrazino), for example, By etching the exposed portion of the substrate 80 by immersing it in a liquid temperature of 100° C.
1) surface appears, and as a result, a rectangular protruding recess 81 having an apex in the depth direction of the substrate is easily formed on the surface of the substrate 81.

The angle θ of the square heel-shaped four portions 81 formed in this way with respect to the substrate surface is approximately 65 degrees (to be exact, the angle θ is 54 degrees and 74 degrees). In the above-mentioned embodiment, a p-n junction is provided in the light receiving element. The solid-state imaging device used for Kucho optical viewing will be explained, and it is also effective for Kuchin image devices. In addition to forming signal processing circuit elements on the entire surface of the substrate, it is also possible to form drive circuit elements for driving the signal processing circuit elements.

(2) Beyond the effects of the invention, as explained in detail, this research enables the formation of light-receiving elements on the entire surface of a semiconductor substrate, dramatically increasing the degree of integration. This has the great effect of realizing an imaging device.

[Brief explanation of the drawing]

FIG. 1 is a schematic top view for explaining a conventional solid-state imaging device; FIG. FIG. 8 is a conceptual top view of a solid-state imaging device arranged in an 8×8 matrix according to the present invention, and FIG. 4 is a process for creating a diffusion layer that electrically connects the light receiving element and the processing circuit element. 1.20: semiconductor substrate, 2, 21: light receiving element, 10, 8
0: p-type Sj-M plate, ll: n-type impurity layer, 12:
[Loading weir, l9: 5ins, 14,81: recess with top in depth direction, 16.22. $2: n-type diffusion layer,
17 Two people shooting light. Figure 1 Figure 2 Figure 3 Figure U Figure 4

Claims (1)

[Claims] A light receiving element having a photoelectric conversion function is disposed on one main surface of a semiconductor substrate, a circuit element for processing signal charges from the light receiving element is disposed on one main surface of the pond, and the light receiving element An impurity layer having a conductivity type opposite to that of the substrate is provided through the substrate to electrically connect an output terminal for signal charges provided in the circuit element to an input terminal for introducing signal charges multiplied by millimeter into the circuit element. A solid-state device characterized by: