KR19990054304A - Solid state imaging device and manufacturing method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid state image pickup device and a method of manufacturing the same. In order to maximize blocking of light in an optical black area (OPB area), a first area and a second area are defined and formed in the first to second areas. A semiconductor substrate having a photoelectric conversion region and a charge transfer region, a first light shielding layer covering a charge transfer region of the first region, a second light shielding layer covering an exposed entire surface of the second region, and the first A first planarization layer covering the second to second light blocking layers and the exposed substrate, a first to third color filter layers formed on the first planarization layer of the first region to correspond to the photoelectric change region of the first region, Covering the second region on the first planarization layer of the second region, the first to third color filter shading layer formed to overlap each other, the front surface exposed to the color filter layer and the color filter shading layer 2nd flattening covered And a microlens formed on the second planarization layer of the first region so as to be equivalent to the photoelectric conversion region, wherein light passes through the color filter shielding layers by overlapping respective color filter shielding layers in the OPB region. It is possible to maximize the light shielding ability in the OPB area, thereby to measure a stable signal in the OPB area, and to stably perform various tests for determining the reliability of the solid state imaging device.

Description

Solid state imaging device and manufacturing method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid state image pickup device and a method of manufacturing the same, and more particularly, to a solid state image pickup device having an improved structure to maximize light blocking in an optical black region (hereinafter referred to as an OPB region) and a method of manufacturing the same. will be.

A solid state image pickup device generates electrons by light, arranges a charge coupled device so as to have a directionality, and detects the signal charges transmitted thereby. In other words, it is a device that transfers the electric charges excited by light through a directional CCD array and then amplifies the signal to obtain an output signal. As shown in FIG. 1, the solid state image pickup device, a device for converting an image signal into an electrical signal, includes a PD array unit formed of unit cells formed of PD and a vertical charge coupled device (VCCD), and a horizontal charge coupled device (HCCD). ), And a signal detection unit. The OPB region is located at the portions except the PD array portion. The signal charges generated and accumulated in the PD are sequentially transferred to the VCCD and the HCCD and output through the AMP.

Since the solid state image pickup device is a device using photoelectric conversion that converts a charge signal generated by light into an electrical signal, evaluation by light is essential when evaluating the characteristics of the device. The OPB region functions to generate a reference signal in the evaluation of the device. That is, the signal in the OPB region is used as a reference signal that can measure the degree of blooming, smear, charge transfer efficiency (CTE), and the like. Accurate evaluation of this reference signal is advantageous for quantitative evaluation of the signal level, which is necessary for obtaining accurate images. Therefore, it is necessary to accurately and stably measure the signal in the OPB area. Signal stabilization in the OPB area can be achieved by maximizing shading in this area to suppress the generation of noise generated by light transmission.

2A to 2C are diagrams for explaining a manufacturing process diagram of a solid state image pickup device according to the related art, and schematically illustrate some cross-sections of the PD array portion and the OPB region.

Referring to FIG. 2A, a substrate 200 in which a PD for generating signal charges and a VCCD, which is a charge transfer region for transferring signal charges generated in the PD in a vertical direction, are alternately formed according to the intensity of light incident by a conventional process. After the insulating layer 21 is formed on the exposed front surface of the Ns, light blocking layers 22-1 and 22-2 are formed on the VCCD to prevent the VCCD from being injected from the light. In this case, the light shielding layer 22-2 of the OPB region may cover not only the VCCD but also the entire OPB region including the PD portion so that extra light does not penetrate the entire surface of the substrate. Thereafter, a protective film 23 for protecting such a solid state image pickup device is formed.

Referring to FIG. 2B, a first planarization layer 24 covering the exposed entire surface is formed. Subsequently, color filter layers 25-1, 25-2, and 25-3 are formed on the first planarization layer 24, respectively. That is, a first resin layer is formed on the first planarization layer 24, and the first color filter layer 25-1 is formed by dyeing and fixing the first resin layer in a first color. By repeating the above steps, the second and third color filter layers 25-2 and 25-3 are formed on the first planarization layer 24, respectively, to form three colors on the first planarization layer 24. The color filter layer is formed sequentially.

Referring to FIG. 2C, after the process of forming the color filter layer is completed, the second planarization layer 26 is formed on the first planarization layer 24 including the color filter layer to planarize the substrate again. Thereafter, the microlens material, which is an acrylic resin, is coated on the second planarization layer 26, and then the applied microlens material is photo-etched to form a microlens material layer positioned on each PD. . Subsequently, a thermal reflow process is performed on the microlens material layer to form a convex lens-type microlens 27.

Thereafter, a subsequent process is performed to complete the manufacture of the solid state imaging device.

However, the above structure has a disadvantage in that the OB region is not properly shielded. That is, the signal in the OPB region is unstable because the signal in the OPB region is not accurately measured due to the generation of noise. As a result, a test for determining the reliability of various solid-state image pickup devices such as blooming, smear, charge transfer efficiency, and the like may be inaccurate.

It is an object of the present invention to provide a solid state image pickup device having an improved structure in which an OPB area can be properly shielded.

The present invention is intended to maximize light blocking ability by preventing light from passing through the color filter layers by overlapping each color filter layer in the OPB region.

According to an embodiment of the present invention, a semiconductor substrate including a photoelectric conversion region and a charge transfer region formed in the first to second regions, and a charge covering region of the first region are defined. A first light shielding layer, a second light shielding layer covering the exposed entire surface of the second region, a first planarization layer covering the first to second light shielding layers and the exposed substrate, and a first planarization layer of the first region First to third color filter layers formed to correspond to the photoelectric change regions of the first region on the top, and first to third overlapping the second regions on the first planarization layer of the second region, respectively. A third color filter shading layer, a second planarization layer covering the color filter layers, the color filter shading layers, and an exposed entire surface, and a second planarization layer on the first region so as to correspond to the photoelectric conversion region; Including microlenses made Is a solid state imaging device.

The present invention provides a process for preparing a semiconductor substrate having a first region and a second region, the photoelectric conversion region and the charge transfer region formed in the first to second regions, and the charge transfer of the first region. Forming a first light shielding layer covering a region and a second light shielding layer covering an exposed entire surface of the second region, and forming a first planarization layer covering the first to second light shielding layers and the exposed substrate; And forming a first color filter layer on a first portion of the first region on the first planarization layer and a first color filter light shielding layer on the second region, and predetermining a first region on the first planarization layer. Forming a second color filter layer positioned at a portion and a second color filter shielding layer overlapping the first color filter shielding layer; and a third color filter layer positioned at a predetermined portion of a first region on the first planarization layer. And the second Forming a third color filter shielding layer overlapping the light shielding layer, forming a second planarization layer covering the color filter layers and the color filter shielding layers and the entire exposed surface, and the first region A method of manufacturing a solid-state image pickup device comprising a bottom surface for forming a microlens corresponding to the photoelectric conversion region on a second planarization layer of the film.

1 is a general plan view of a solid state imaging device

2A to 2C are manufacturing process diagrams of a solid state image pickup device according to the related art.

3 is a cross-sectional view of a solid state image pickup device according to the present invention.

4A to 4D are manufacturing process diagrams of the solid state image pickup device shown in FIG.

3 shows a cross-sectional structure of the solid state image pickup device according to the present invention, and shows the PD array unit in addition to the OPB region. The OPB region has a plurality of cells similar to the PD array portion.

In the PD array unit, as in a conventional structure, an exposure of the semiconductor substrate 300 on which the PD for generating signal charges according to the light intensity and the VCCD, which is a charge transfer region for transferring signal charges generated in the PD in a vertical direction, are alternately formed. An insulating layer 31 is formed on the entire surface, a light shielding layer 32-1 for preventing the VCCD from being injected from light is formed on the VCCD, and a protective film 33 for protecting such a substrate is formed. . The first planarization layer 34 is formed thereon, and the first, second and third color filter layers 35-1, 35-2, and 35-3 are formed on the first planarization layer 34. The second planarization layer 36 and the microlenses 37 corresponding to the respective PDs are formed thereon.

The OPB region is formed in a structure similar to the above-described PD array portion, except that the first, second and third color filter layers 35a, 35b and 35c overlap. The insulating layer 31 is formed on the exposed front surface of the semiconductor substrate 300 on which the PD and VCCD are alternately formed, and the light shielding layer 32-2 is formed on the front surface of the semiconductor substrate 300, and the protective film 33 protecting the substrate. ) Is formed. The first planarization layer 34 is formed thereon. The second planarization layer 36 is positioned on the first planarization layer 43 so as to overlap the first, second, and third color filter light blocking layers 35a, 35b, and 35c, and has a flat front surface thereon. Since the first, second and third color filter light shielding layers 35a, 35b and 35c overlap on the first planarization layer 34, light cannot be transmitted. Therefore, the light blocking ability of the OBP region can be improved as compared with the prior art. In this case, each of the first, second and third color filter layers may have a color of RED, GREEN, BLUE, or may have a color of CYAN, MAGENTA, YELLOW.

4A to 4C are manufacturing process diagrams of the solid state image pickup device according to the present invention described above.

Referring to FIG. 4A, a semiconductor substrate 300 having a PD for generating signal charges according to the intensity of light incident by a conventional process, and a VCCD which is a charge transfer region for transferring signal charges generated in the PD in a vertical direction. After the insulating layer 31 is formed of an insulating material, such as silicon oxide, on the exposed front surface of the (), the light shielding layers 32-1 and 32-2 are formed on the VCCD to prevent the VCCD from being injected from the light. . In this case, the light shielding layer 32-2 of the OPB region may cover the entire OPB region including the PD portion as well as the VCCD so that extra light does not penetrate the substrate. Thereafter, a protective film 33 for protecting such a solid state image pickup device is formed.

Referring to FIG. 4B, a first planarization layer 34 covering the exposed entire surface is formed. Subsequently, a first color filter light shielding layer 35a covering the entire surface of the first color filter layer 35-1 and the OBP region is formed in a portion corresponding to the first PD on the first planarization layer 34. That is, the first color filter layer 35-1 is formed on the first planarization layer 34 in the PD array portion and the OBP region in a predetermined pattern, and is dyed and adhered to the first color. And a first color filter light shielding layer 35a. In this case, the first color may be RED or CYAN.

Referring to FIG. 4C, the second color filter light shielding layer 35 may be disposed on the second color filter layer 35-2 and the first color filter light shielding layer 35a at a portion corresponding to the second PD on the first planarization layer 34. 35b). That is, a second resin layer is formed on the exposed first planarization layer 34 in a predetermined pattern in the PD array portion and the OBP region, and is dyed and fixed in a second color to form the second color filter layer 35-. 2) and the second color filter light shielding layer 35b. Then, the above process is repeated to form the third color filter light blocking layer 35c on the third color filter layer 35-3 and the second color filter layer. In this case, the second color may be GREEN or MAGENTA, and the third color may be BLUE or YELLOW.

Referring to FIG. 4D, after the process of forming the color filter layer and the color filter light shielding layer is completed, the color filter layers 35-1, 35-2, 35-3 and the color filter light shielding layers 35a, 35b and 35c are completed. The second planarization layer 36 is formed on the first planarization layer 34 including) to planarize the substrate again. Thereafter, a microlens material, which is an acrylic resin, is coated on the second planarization layer 34, and then the applied microlens material is photo-etched to form a microlens material layer positioned on each PD. . Subsequently, a thermal reflow process is performed on the microlens material layer to form a convex lens-type microlens 37.

Thereafter, a subsequent process is performed to complete the manufacture of the solid state imaging device.

The present invention can maximize light blocking ability in the OPB region by overlapping each color filter layer in the OPB region to prevent light from entering the OPB region. Therefore, a stable signal in the OPB area can be measured, and various tests for determining the reliability of the solid state imaging device can be performed stably.

Claims (3)

A semiconductor substrate having a first region and a second region defined therein, the semiconductor substrate including photoelectric conversion regions and charge transfer regions formed in the first to second regions; A first light blocking layer covering the charge transfer region of the first region; A second light blocking layer covering an exposed front surface of the second region; A first planarization layer covering the first to second light blocking layers and the exposed substrate; First to third color filter layers formed on the first planarization layer of the first region to correspond to the photoelectric change region of the first region; First to third color filter light blocking layers covering the second region on the first planarization layer of the second region, and overlapping the second region; A second planarization layer covering the color filter layers and the color filter light blocking layers and the entire exposed surface; And a microlens formed on the second planarization layer of the first region to be equivalent to the photoelectric conversion region. The method according to claim 1, And the first to third color filter layers and the first to third color filter light blocking layers are CYAN, MAGENTA, and YELLOW, respectively. Preparing a semiconductor substrate having a first region and a second region, the semiconductor substrate having photoelectric conversion regions and charge transfer regions formed in the first to second regions; Forming a first light blocking layer covering the charge transfer region of the first region and a second light blocking layer covering an exposed entire surface of the second region; Forming a first planarization layer covering the first to second light blocking layers and the exposed substrate; Forming a first color filter layer positioned at a predetermined portion of the first region on the first planarization layer and a first color filter shielding layer in the second region; Forming a second color filter layer positioned at a predetermined portion of the first region on the first planarization layer and a second color filter shielding layer overlapping the first color filter shielding layer; Forming a third color filter layer positioned at a predetermined portion of the first region on the first planarization layer and a third color filter shielding layer overlapping the second color filter shielding layer; Forming a second planarization layer covering the color filter layers and the color filter light blocking layers and the entire exposed surface; And a cavity for forming a microlens corresponding to the photoelectric conversion region on the second planarization layer of the first region.