JPS60167477A - Photosensor - Google Patents

Abstract

PURPOSE:To improve the yield without drop of the resolution in the aperture width direction by a method wherein each photo diode element is split into a plurality of photo diode regions, so as to be used by selecting a region of least ununiformity from among the photo diode regions corresponding to the same split section. CONSTITUTION:Each photo diode element 10 is split into a plurality of photo diode regions 11: this photo diode region 11 is an N<+> type diffused layer produced by ion implantation of e.g. phosphorus. The N<+> type diffused layer of respective photo diode elements 10 are alternately coupled with a photo gate, a transfer gate, and a CCD region in the vertical directions of the figure. The first line is the photo diode region 11 opened between light shielding films 15 and 13, the second is the photo diode region 11 opened between light shielding films 13 and 14, and the third is the photo diode region 11 opened between light shielding films 14 and 16. Therefore, the line of least non-uniformity can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a photosensor, and specifically relates to a technique that is effective when applied to a light receiving section of a photosensor.

[Background technology] CCD (Charge Coupled Device)
e) Photosensors are generally widely used. This C
A current problem in CD photosensors is the non-uniformity of elements in terms of yield or characteristics.

The cause of this will be specifically explained with reference to the one-dimensional photo sensor 1 to the light receiving portion of the sensor.

FIG. 1 is a schematic plan view of a photodiode section of a one-dimensional food sensor. In the figure, reference numeral 1 indicates a semiconductor substrate such as P
There is an N+ type resistive diffusion layer formed within the type well to form a photodiode region. The N+ type resistive diffusion layer photodiode region 1 is coupled to a photogate, a transfer gate and a COD region to form a CCD photosensor in a well known manner. In the N+ type resistive diffusion layer photodiode region 1, the aperture width Y of the light receiving surface is determined by a light shielding film 2 made of aluminum or the like, and along the aperture length direction, there is a relatively thick layer between each photodiode region 1. 5i
A channel stopper is provided for the 02 film 3 and the P+ type impurity semiconductor region below it, and the opening length X is determined (for example, in the magazine R Semiconductor
WorldJ December 1982 issue, p50-57, etc.).

By the way, in the manufacturing process of such a -dimensional hook 1 sensor, foreign matter 4a on the N+ type scattering layer 1 or N+
A shape defect 4I:) of the type scattering layer 1 may occur within the opening. Similarly, a defective shape 5 of the light shielding film 2 that determines the opening width yl also occurs. For this reason, the light-receiving sensitivity of the photodiode region l where the foreign matter 4a or the defective shape 4F>, 5 has occurred changes, which impedes the uniform sensitivity of the -dimensional photosensor, and those that exceed the allowable range are considered defective, resulting in a decrease in yield. The inventors have discovered that there is a problem in that

One way to solve the above problem is to increase the opening width Y and eliminate the foreign matter 4a or the defective shape 4b.

It is conceivable to increase the margin of tolerance for 5. However, in the current one-dimensional food sensor in which the aperture length
If the margin is increased to m, there is a problem that the resolution in the aperture width Y direction decreases, which is not practical.

[Objective of the Invention] An object of the present invention is to provide a photosensor that can make the characteristics uniform and improve the yield without reducing the resolution in the aperture width direction of each photodiode element of the photosensor. be.

The above and other novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[Summary of the Invention] A brief overview of typical inventions disclosed in this application is as follows.

In other words, each photodiode element constituting the photosensor is divided into a plurality of photodiode regions, and photodiode regions corresponding to the same division are selectively used, resulting in a photodiode region with uniform characteristics. You can choose from a variety of photosensors. Therefore, it is possible to achieve a photosensor with uniform characteristics and improved yield without reducing the resolution in the aperture width direction.

[Embodiment 1] A first embodiment of the one-dimensional food sensor of the present invention will be described with reference to Fig. 3-2. In the first embodiment, each photodiode element has a plurality of N+ type expanded I in the aperture width direction.
A K-layer photodiode element is formed, and a gate electrode and a light-shielding film on the gate electrode are formed between these photodiode regions.

In FIG. 2, photodiode elements 10 (four sets in the embodiment) are formed in a P-type well region formed in a semiconductor substrate. Each photodiode element 10 is divided into a plurality of photodiode regions 11 (three in this embodiment), and each photodiode region 11 is an N+ type scattering layer into which ions of phosphorus or the like are implanted, for example. Note that the N-type diffusion layer of each photodiode element 10 is alternately formed into a photogate, a transfer gate, and a C-type diffusion layer in the vertical direction of the figure.
It is bound to the CD region. Each photodiode area 1
The aperture length X of 1 is set to approximately 7 μm, and a relatively thick 5i
A channel strike 4- brim of the 02 film 12 and the P+ type impurity semiconductor region below it is formed.

On the other hand, the aperture width Y of each photodiode element 10 is determined by the light-shielding films 13 and 14 made of aluminum or the like provided between the N0 type diffusion layers 11 and the light-shielding films 13 and 14 made of aluminum or the like that determine the overall aperture. It is determined by the membranes 15 and 16. On the surface of the P-type well in the area where the light shielding film 13, 14 and each photodiode element 1, 0 intersect,
A gate is formed for each, and all gates included in the same light blocking film 13 or 14 are commonly connected. The aperture width Y is, for example, 7 μm, and the light interference [1
In accordance with the optical system of a facsimile machine, an optical reader, etc., the width of 3 and 14 is set to such a length that the light hitting the photodiode areas 11 adjacent in the vertical direction in the figure can be sufficiently ignored.

By using a one-dimensional photo sensor with such a structure, the photodiode areas 11 corresponding to the same division section can be
This results in three lines. That is, the first row is a photodiode region 11 that is opened between the light shielding films 15 and 13.
．． The second row is the photodiode area 1-1 opened between the photo-barrier films 13.14. The third row is the photo-barrier film 14.1
This is a photodiode region 11 having an opening between 6 and 6. Therefore, for example, the photodiode region 11 of the first row
If the non-uniformity is significant, the photodiode regions 11- in the second or third row can be used. Note that a high level of binary logic is applied to each gate to electrically connect the photodiode regions 11 in each photodiode element 10. In this embodiment, from among the photodiode regions 11 in each row, the row with the least undesirability can be selected and the photodiode 1 region 11 in the Y row can be used.

[Embodiment 2] In the second embodiment, each photodiode element has a plurality of N+ type scattered layer photodiode regions formed in the aperture width direction, and the photodiode regions of each photodiode element are electrically parallel to each other. It is characterized in that it is connected to the photogate, transfer gate, and CCD area in a connection relationship.

In FIG. 3, a large number of I-diodes 20 (four sets in the embodiment) are formed in a P-type well region formed in a semiconductor substrate. Each photodiode element 20
is a plurality of (two in the example) photodiode regions 2
The photodiode region is divided into 1.22 parts, and this photodiode region has an N+ type scattering layer into which ions of phosphorus or the like are implanted. The photodiode regions 21 and 22 constituting each photodiode element 20 are connected in parallel using a conductive material such as aluminum.
Connected to the CD area. Each photodiode area 2
The opening length X of 1.22 is set to, for example, 7 μm, and a relatively thick 5i02 film 24 and a channel stopper of the P+ type impurity semiconductor region below it are formed between the photodiode regions 21 in the direction of the opening length X. There is.

By using a one-dimensional food sensor having such a structure, two rows of photodiode regions 21 and 22 corresponding to the same division can be formed.

That is, the first row is formed by four photodiode regions 21 or IJ shadows, and the second row is formed by the same four photodiode regions 22. Therefore, in this embodiment as well, for example, the photodiode region 2 of the second row
1, the photodiode region 22 in the first row can be used. Thereafter, an opening having an opening width Y can be formed in the first row photodiode region 22 using a light shielding film 23 such as a black filter.

In the first embodiment, the light-shielding films 13, 14°15
．． 16, photodiode regions 11 in each row are formed.
Although the rows were selected by inspecting the non-uniformity of -, in the second embodiment, the formation of the light blocking film 23 was carried out after the row selection inspection.

[Effects] As explained above, in the photosensor of the present invention, each photodiode element is divided into a plurality of photodiode regions, so that the photodiode regions corresponding to the same division are divided into the most nonuniform regions. Since it is possible to select and use a material with a small number of particles, it has the effect that uniformity is good and yield can be improved without deteriorating the resolution in the aperture width direction.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor.

[Field of Application] The present invention is applicable not only to -dimensional photosensors but also to semiconductor devices that form openings in photodiodes such as CCD solid-state imaging devices and MO8 solid-state imaging devices.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of the vicinity of the photodiode opening of a conventional one-dimensional food sensor, and FIGS. 2 and 3 are photos for explaining the first and second embodiments of the one-dimensional food sensor of the present invention, respectively. FIG. 3 is a plan view of the area around the diode opening. 1.10.20...Photodiode element, 2,13
, 14, 15, 16.23... photoreflective film, 3. ]
, 2.24...S i02 film, 4a... Foreign matter, 4b
, 5... Shape defect, 11, 21.22... Photodiode region. 11-)

Claims (1)

[Claims] 1. A plurality of photodiode elements each having a plurality of photodiode regions divided in the aperture width direction of a photoreceptor film are formed in the aperture length direction, and each photodiode element has photodiodes corresponding to the same division. A photosensor characterized by selectively using a region.