KR100339432B1 - Solid state image sensing device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device capable of increasing charge transfer efficiency by varying the structure of a VH interface portion. A vertical charge transfer region for transferring charge in a vertical direction, a horizontal charge transfer region for horizontally transferring vertically transferred charges, and poly gates repeatedly configured on the vertical and horizontal charge transfer regions, A second poly gate in the center of the interface portion of the vertical charge transfer region and the horizontal charge transfer region, a second poly gate partially overlapping in a direction parallel to one side thereof, and first and second on the horizontal charge transfer region on the other side thereof; The poly gate is extended to partially overlap the third poly gate.

Description

Solid state image sensing device {Solid state image sensing device}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device, and more particularly, to a solid-state image pickup device capable of increasing charge transfer efficiency by changing a structure of a V-H interface portion.

Hereinafter, a solid state image pickup device according to the related art will be described with reference to the accompanying drawings.

1 is a layout view of a V-H interface region of a solid-state imaging device of the prior art, and FIG. 2 is a structural cross-sectional view of the solid-state imaging device of the prior art.

FIG. 1 illustrates the structure of an interface region between a VCCD region VCCD 10 and a HCCD region 20.

In the solid-state imaging device, a plurality of photoelectric conversion regions (PD) 1 are regularly arranged, and a vertical charge transfer region for transferring photoelectrically converted charges in a vertical direction between each photoelectric conversion region 1 2), and is largely composed of the horizontal charge transfer region 5 which horizontally transfers the vertically transferred charges so as to be sensed in the floating diffusion region.

On the vertical charge transfer region 2, the first and second poly gates 3 and 4, which are electrically separated from each other and partially overlap, are repeatedly configured.

Four phases of vertical charge transfer clocks are applied to the first and second poly gates 3 and 4.

On the horizontal charge transfer region 5, the first and second poly gates 6 and 7 which are electrically separated from each other and partially overlap each other are repeatedly configured to apply a two phase horizontal charge transfer clock.

FIG. 2 is a cross-sectional view taken along the line A-A 'of FIG. 1, in which the first and second poly gates 3 and 4 (the same structure as in FIGS. 6 and 7) are first placed on the BCCD region in the VH interface region. It can be seen that the first poly gate 3 is formed and a part overlaps with the second poly gates 4.

In this way, when the image charge is generated in the photoelectric conversion regions 1, the vertical charge is transferred in the vertical direction through the vertical charge transfer region 2 for the charge transfer clock applied to the first and second poly gates 3 and 4. Is sent.

Charges transferred through the vertical charge transfer region 2 are then transferred in the horizontal direction by the charge transfer clocks applied to the first and second poly gates 6 and 7 on the horizontal charge transfer region 5 to float. Moved to the diffusion area.

In order to increase the saturation level of the vertical charge transfer region, a BCCD (Buried CCD) region constituting the vertical charge transfer region should be large, but there is a limit in the high pixel trend of the device.

Therefore, other methods have to be proposed to increase the saturation level in the vertical charge transfer region.

Such a solid-state imaging device of the prior art has the following problems.

In order to increase the saturation level of the vertical charge transfer region, the BCCD region should be formed wide, but this is difficult due to the structure of the V-H interface.

That is, since the second poly gate or the first poly gate of the HCCD cannot cover the entire BCCD region, charge transfer becomes difficult.

In FIG. 1, the second poly gate on the HCCD region positioned at the end of the vertical charge transfer region is expanded, but this is limited.

This is because the process margin is not secured because the first and second poly gates on the HCCD region and the first and second poly gates on the VCCD region must be electrically separated.

Therefore, basically, as in ⓐ part of FIG. 1, the V-H interface part should have a certain distance.

This separation distance is the minimum process margin that must be secured in the poly gate patterning process.

As described above, the solid-state imaging device of the prior art does not increase the saturation level of the vertical charge transfer region, thereby degrading the charge transfer efficiency.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem of the solid-state imaging device of the prior art, and an object thereof is to provide a solid-state imaging device capable of increasing charge transfer efficiency by changing the structure of the V-H interface portion.

1 is a layout view of the V-H interface region of the conventional solid-state imaging device

2 is a structural cross-sectional view of a solid-state imaging device of the prior art

3 is a layout view of the V-H interface region of the solid-state imaging device according to the present invention;

4 is a layout view of the V-H interface region of the solid-state imaging device according to the present invention;

Explanation of symbols for the main parts of the drawings

31. Photodiode region 32. Vertical charge transfer region

33. The first poly gate 34. The second poly gate

35. Third poly gate 36. Horizontal charge transfer region

In the solid-state imaging device according to the present invention for achieving the above object, a plurality of photodiode regions are arranged regularly, the vertical charge transfer for transferring the photoelectric conversion charge in the vertical direction is configured between each photodiode region An area, a horizontal charge transfer region for horizontally transferring vertically transferred charges, and poly gates repeatedly configured on the vertical and horizontal charge transfer regions, wherein the interface of the vertical charge transfer region and the horizontal charge transfer region At the center of the portion, a third poly gate is partially overlapped on one side thereof, and a second poly gate partially overlapped in a direction parallel thereto, and on the other side, the first and second poly gates on the horizontal charge transfer region are extended to partially overlap the third poly gate. It is characterized in that the overlap.

Hereinafter, the solid-state imaging device according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a layout view of the V-H interface region of the solid-state imaging device according to the present invention, and FIG. 4 is a layout view of the V-H interface region of the solid-state imaging device according to the present invention.

In the solid-state imaging device according to the present invention, a third poly gate separate from the first and second poly gates is formed in the VH interface to maximize the size of the vertical charge transfer region. The center portion is shown centering on the interface portion between the vertical charge transfer region forming region 40 and the horizontal charge transfer region forming region 30 including 31.

The structure has a plurality of photodiode (PD) 31 arranged regularly, the vertical charge transfer region 32 for transferring the photoelectric conversion charge in the vertical direction between each photodiode region 31 ) Is largely composed of a horizontal charge transfer region 36 which horizontally transfers the vertically transferred charges to be sensed in the floating diffusion region.

The first and second poly gates 33 and 34 which are electrically separated from each other and partially overlap each other are formed on the vertical charge transfer region 32.

Four phases of vertical charge transfer clocks are applied to the first and second poly gates 33 and 34 on the vertical charge transfer region 32.

The first and second poly gates 33 and 34, which are electrically separated from each other and partially overlap each other, are repeatedly configured on the horizontal charge transfer region 36 to apply a two-phase horizontal charge transfer clock.

And the detailed configuration in the VH interface portion is such that a vertical charge transfer region 32 having a width of at least the size of the first poly gate 33 + the second poly gate 34 on the HCCD region is connected to the horizontal charge transfer region 36. And a third poly gate 35 in the center of the interface portion.

On the one side of the third poly gate 35, that is, the photodiode region, a second poly gate 34 overlapping a portion of the third poly gate 35 is formed, and on the HCCD side of the third poly gate 35. The first and second poly gates 33 and 34 on the HCCD region extend to overlap the third poly gate 35.

4 is a cross-sectional view taken along the line B-B 'of FIG. 3, wherein a third poly gate 35 is formed at the center of the VH interface portion, and a second poly gate is formed at one side of the third poly gate 35. The first and second poly gates 33 and 34 are formed on the other side. Here, the first poly gates 33 and the vertical charge transfer region 32 above the horizontal charge transfer region 36 are formed. First poly gates 34 are formed in the same process, and the second poly gates 34 above the horizontal charge transfer region 36 and the second poly gates 34 above the vertical charge transfer region 32 are formed. The third poly gate 35 may be formed separately from the first and second poly gates 33 and 34. That is, the third poly gate ( 35 and the first and second poly gates 33 and 34 above the vertical charge transfer region 32 and the horizontal charge transfer respectively, respectively. Region 36 the first and second poly gate 33 of the upper 34 are overlapped, so need not be directly processing margin in the formation process of the gate poly is sufficiently hoekbo.

As described above, the solid-state imaging device according to the present invention may form the third poly gate before the first and second poly gates are formed in the VH interface region, thereby overlapping the third poly gate even when the VCCD region is wider. Since all the charges are transferred by the gate, the charge transfer efficiency can be improved.

In this manner, when the image charge is generated in the photodiode regions 31, the vertical charge transfer region 32 is applied in the vertical direction for the charge transfer clock applied to the first and second poly gates 33 and 34. Is sent.

Charges transferred through the vertical charge transfer region 32 are then transferred in the horizontal direction by the charge transfer clocks applied to the first and second poly gates 33 and 34 on the horizontal charge transfer region 36 to float. Moved to the diffusion area.

Here, the charge transfer in the V-H interface region is smoother by the third poly gate, and the vertical charge transfer region can be formed wider by the third poly gate, thereby increasing the saturation level of the vertical charge transfer region.

Such a solid-state imaging device according to the present invention can increase the saturation level of the vertical charge transfer region, thereby improving the sensitivity of the device.

In addition, there is an effect of sufficiently securing the process margin and improving the characteristics of blooming, smear and the like.

Claims (2)

A plurality of photodiode regions are regularly arranged and arranged between each photodiode region, a vertical charge transfer region for transferring photoelectrically converted charges in the vertical direction, and a horizontal charge transfer region for horizontally transferring the vertically transferred charges again. And comprise poly gates repeatedly configured on the vertical and horizontal charge transfer regions, A third poly gate in the center of the interface portion of the vertical charge transfer region and the horizontal charge transfer region, a second poly gate partially overlapping in a direction parallel to one side thereof, and a first poly gate on the other side thereof; 2. The solid-state imaging device as claimed in claim 2, wherein the two poly gates extend to partially overlap the third poly gate. 2. The solid-state imaging device as claimed in claim 1, wherein the vertical charge transfer region has a width of at least the size of the first poly gate + the second poly gate on the horizontal charge transfer region.