KR19980056449A - Color solid-state imaging device and manufacturing method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color solid-state imaging device and a method of manufacturing the same, wherein the charge transfer region (VCCD) formed at a predetermined interval on the semiconductor substrate, and the charge transfer region are alternately arranged. A photoelectric conversion region PD formed on the semiconductor substrate, a planarization film formed on the exposed substrate, and first to third colors formed in a hemispherical shape on the planarization film corresponding to the photoelectric conversion region. It includes a color filter layer and a micro lens formed to cover each of the color filter layers. Since the color filter layer is formed in a hemispherical shape, the surface thereof can be made uniform, and the process can be simplified in this process.

Description

Color solid-state imaging device and manufacturing method thereof

1 is a manufacturing process diagram of a color solid-state imaging device according to the prior art

2 is a cross-sectional view of a color solid-state imaging device according to the present invention.

3 is a manufacturing process diagram of a color solid-state imaging device according to the present invention.

* Explanation of symbols for main parts of the drawings

30: semiconductor substrate. 31-1,31-2,31-3: photodiode.

32: insulation layer. 33: charge transfer region.

35: light shielding layer. 36: planarization film.

38-1, 38-2, 38-3: color filter layer. 40: micro lens

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color solid-state image pickup device and a method of manufacturing the same, and more particularly, to a color solid-state image pickup device and a method of manufacturing the same, by forming a color filter layer in a hemispherical shape to make the surface uniform and simplify the process.

A solid-state imaging device is an apparatus for generating electrons by light, arranging charge coupled devices to have a directionality, and detecting signal charges transmitted thereby. In other words, it is a device that transfers the excitations excited by light through a directional CCD array, and then amplifies this signal to obtain a predetermined output signal.

The solid-state image pickup device, which converts an image signal into an electrical signal, includes a photoelectric conversion part that absorbs light to generate electrons, and a charge that transfers the charge generated in the photoelectric conversion part to a predetermined region by the movement of a dynamic potential well. It consists of a transmission part and a signal detection part which detects a signal from the conveyed electric charge.

Fig. 1 briefly shows a manufacturing process diagram of a color solid-state imaging device according to the prior art.

As shown in Fig. 1 (a), the photodiodes 11-1, 11-2, 11-3 and photodiodes are generated for generating signal charges according to the intensity of light incident by a conventional process. VCCD (Vertical Charge Coupled Device) 12, which is a charge transfer region, is alternately formed on the substrate 10, and the photodiodes 11-1, 11-2, 11-3 and VCCD ( The pad 12 is formed on one side of the substrate except for the portion where the 12 is formed, thereby forming a monochrome solid-state image pickup device. 11-1 is a photodiode corresponding to the first color, 11-2 is a photodiode corresponding to the second color, and 11-3 is a photodiode corresponding to the third color.

Subsequently, after the insulating layer 13 is formed of an insulating material such as silicon oxide on the exposed front surface, a portion of the light blocking layer 14 positioned on the top of the VCCD 12 to prevent the VCCD 12 from being injected from the light. To form. Then, the protective film 15 which protects such a solid-state image sensor is formed.

Subsequently, as shown in FIG. 1B, a first planarization layer 17 is formed to cover the exposed entire surface. Thereafter, color filter layers 18-1, 18-2, and 18-3 are formed on the first planarization layer 17. That is, a resin layer is formed on the first planarization layer 17, the resin layer is dyed and fixed in the first color, and the colored resin layer is photo-etched to form the first color filter layer 18-1. The above steps are repeated to form second and third color filter layers 18-2 and 18-3 on the first planarization layer 17, respectively. Thus, three color filter layers 18-1, 18-2, and 18-3 are sequentially formed on the first planarization layer 17. As shown in FIG.

Subsequently, as shown in FIG. 1 (c), after the process of forming the color filter layer is completed, the first flattening layer 17 including the color filter layers 18-1, 18-2, and 18-3 is formed. The planarization layer 19 is formed to planarize the substrate again. Subsequently, a microlens material, which is an acrylic resin, is coated on the second planarization layer 19, and then a photolithography process is performed on top of each photodiode 11-1, 11-2, and 11-3. Only the microlens material is patterned so that the microlens material layer 20 is formed.

Subsequently, as shown in FIG. 1 (d), the patterned microlens material layer 20 is subjected to a heat reflow process to thereby form a convex lens-type microlens 21 for each photodiode 11-. 1) It is formed on the 2nd planarization layer 19 above (11-2) and (11-3).

Subsequently, as shown in FIG. 1E, a photoresist film is coated on the second planarization layer 19 on which the microlens 21 is formed, and the photoresist film on the pad 12 is removed by preliminary etching. The second planarization layer 19 is exposed. Thereafter, after the pad 12 is exposed by etching the second planarization layer and the first planarization layer, and removing the remaining photoresist film, a color solid-state imaging device having a cross section as shown in the drawing can be manufactured.

When the color solid-state imaging device fabricated in this manner is applied to a camera, the light incident through the camera lens is focused by the micro lens 21, and the light focused by the micro lens 21 is the color filter layer 18. Selected through. That is, the first color filter layer 18-1 of the color filter layers selectively transmits only the light of the first color among the light focused by the microlens 21, so that the photodiode 11 corresponding to the first color of the plurality of photodiodes is selected. -1), the second color filter layer 18-2 selectively transmits only the light for the second color and applies it to the photodiode 11-2 corresponding to the second color, and the third color filter layer 18 -3) selectively transmits only the light for the third color and applies it to the photodiode 11-3 corresponding to the third color.

Therefore, the light incident on each photodiode 11 is photoelectrically converted to generate signal charges, and the charges generated by the photodiode 11 are transferred to the VCCD 12 by a signal transmission operation of a conventional solid-state image pickup device. Sent to HCCD (not shown in the figure). Subsequently, the signal charge transmitted to the HCCD is sensed by a voltage by floating diffusion at the end of the device, and then amplified by an amplifier (not shown) to be transmitted to the peripheral circuit.

As such, the light collected by the microlens passes through the color filter layer, and only light of a specific wavelength band corresponding to the predetermined color filter layer on each pixel is selectively transmitted. In this case, since the light blocking layer is only open on the photodiode, the light blocking layer is incident only on the open photodiode. Therefore, the light collected from the microlens should be incident on the photodiode through the color filter layer accurately. To this end, the color filter layer must cover a larger area as the distance from the photodiode to cover the incident light, it should be made in a uniform form without the simi or Mura.

However, the color solid-state imaging device as described above must undergo a series of pre-etching steps to form a color filter layer, which causes surface irregularities such as staining or mura on the pattern surface during development.

In addition, since the microlenses are formed through the same photolithography process, accurate alignment between the color filter layer and the microlenses should be possible. For this purpose, a planarization layer should be formed before the color filter layer and before the microlens formation. The color filter layer, which is far from the photodiode, should be formed as wide as possible. Therefore, since a planarization layer exists between the microlens and the color filter layer, light tends to be scattered, and a problem of difficulty in adjusting the focal length to the photodiode due to the distance error between the microlens and the color filter layer occurs. In addition, since the planarization layer must be formed again after the color filter layer is formed, the overall process is complicated, manufacturing time is long, and there is a problem in that the thickness of the device becomes thick.

Therefore, an object of the present invention is to form a hemispherical color filter layer, to correct the uniformity of the surface of the color filter layer in the process of forming it, and to simplify the manufacturing process.

To this end, the present invention provides a color solid-state imaging device, comprising: a semiconductor substrate, a charge transfer region formed at regular intervals on the semiconductor substrate, and a charge transfer region formed alternately with the charge transfer region on the semiconductor substrate; A photoelectric conversion region, a planarization film formed on the exposed substrate, a hemispherical shape formed on the planarization film, and covering the color filter layers of the first to third colors corresponding to the photoelectric conversion region, and the respective color filter layers. It includes a micro lens formed so that.

In addition, the present invention provides a method for manufacturing a color solid-state imaging device, the method comprising the steps of forming a charge transfer region located at a predetermined interval on the semiconductor substrate, and the charge transfer region between the charge transfer region to be alternately arranged with the charge transfer region; Forming a photoelectric conversion region on the semiconductor substrate, forming a planarization film on the exposed substrate, and forming a color filter layer of the first to third colors corresponding to the photoelectric conversion region in a hemispherical shape on the planarization film. And forming a micro lens covering each of the color filter layers.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

2 shows a cross-sectional view of a color solid-state imaging device according to the present invention.

The color solid-state image pickup device according to the embodiment of the present invention includes a plurality of charge transfer VCCDs 33 and a plurality of charge transfer VCCDs 33 arranged alternately with the VCCDs 33 at predetermined intervals on the substrate 30. On the one side of the substrate 30 excluding a plurality of photodiode 31-1, 31-2, 31-3 corresponding to the first to third colors and the photodiode and the VCCD 33 The pad 37 is located. The light shielding layer 35 is formed on the insulating layer 32, and covers only the VCCD 33, and the planarization film 36 is formed to planarize the entire surface of the substrate 30 except for the pad 37. have. Then, a plurality of color filter layers 38-1, 38-2 and 38-3 corresponding to the first to third colors positioned on the planarization film 36 on each photodiode 31 are formed. A plurality of micro lenses 40 is formed thereon which covers the color filter layer in its shape. Each color filter layer 38 and microlens 40 have a hemispherical shape in which the edge portion is rounded. The first color filter layer 38-1 of the plurality of color filter layers is formed corresponding to the photodiode 31-1 of the first color, and the color filter layer 38-2 of the second color is a photo of the second color. In the diode 32-2, the color filter layer 83-3 of the third color is formed on the microlens 40 corresponding to the photodiode 31-3 of the third color.

Fig. 3 shows a manufacturing process diagram of the color solid-state imaging device of the present invention having such a structure.

First, as shown in Fig. 3A, a plurality of photodiodes 31 and VCCDs 33 are alternately formed on a substrate 30 in a conventional manner, and then these photodiodes 31 and VCCDs are formed. The pad 37 is formed on one side of the substrate 30 except for the portion on which the 33 is formed to manufacture a monochrome solid-state imaging device. At this time, the photodiode corresponding to the first color among the plurality of photodiodes is referred to as 31-1, the photodiode corresponding to the second color is referred to as 31-2, and the photodiode corresponding to the third color is referred to as reference number 31-3. Represented by respectively.

Thereafter, the insulating layer 32 is formed of an insulating material such as silicon oxide on the exposed entire surface by a conventional method, and then the VCCD 33 is provided with the light blocking layer 35 for preventing light from being injected into the VCCD 33. It is formed in the portion of the insulating layer 32 where the.

Subsequently, as shown in FIG. 3 (b), the BPG (Boro-Phospho Slicate Class) is applied to the entire surface to form a planarization film 36, and only the pad 37 is opened through a photolithography process. In this case, the planarization layer 36 formed of BPSG simultaneously performs the function of the planarization layer formed to fill the existing protective film and the surface unevenness generated in the protective film. In the process of applying the BPSG, as shown in the figure, it is preferable to form a slight curvature on the surface. The planarization film 36 thus formed is formed to protect the substrate from the beginning and to be flattened, so that the photodiode The distance from the color filter layer formed later is narrowed.

Subsequently, as shown in Fig. 3C, color filter layers 38-1, 38-2 and 38-3 are formed on the planarization film 36. Figs. At this time, the color filter layer to be formed is a little thick instead of the existing flat and flat, it may not be an exact rectangular parallelepiped shape.

That is, a resin layer is formed on the planarization film 36, the resin layer is dyed and fixed in the first color, and the colored resin layer is photo-etched to form the first color filter layer 38-1. The above steps are repeated to form second and third color filter layers 38-2 and 38-3 on the planarization film 36, respectively. As a result, the color filter layers are sequentially formed on the planarization film 36.

Then, as shown in Fig. 3 (d), the patterned color filter layer is subjected to a heat reflow process, and then the hard baking process is performed to perform color filter layers 38-1, 38-2 and 38-38. 3) is formed into a hemispherical shape. In this process, the surface unevenness, such as the surface of the surface, or mura or residual film, is corrected together.

The color filter layer formed by the photolithography process is a negative photosensitive film, which melts and repels during the heat reflow process. In other words, the bonding structure in the photosensitive film itself is changed by heat, and its edge is rounded. Subsequently, when the hard baking step is performed, it is hardened in this state, and as shown in the figure, a hemispherical color filter layer is formed. The hard baking process is at a somewhat higher temperature than the thermal reflow process.

Then, as shown in Fig. 3 (e), a microlens material is applied to the exposed entire surface. Accordingly, the curvature of the material layer 40 for microlenses applied to contact the hemispherical color filter layers 38-1, 38-2 and 38-3 is automatically aligned so that the hemispherical color filter layer is aligned. The surface of (39) is shown as it is.

As shown in Fig. 3 (f), the microlens material layer is anisotropically etched to cover the hemispherical color filter layers 38-1, 38-2 and 38-3 in its shape. The micro lens 41 is formed. At this time, the material layer for the microlens covered on the pad 37 is also etched and exposed.

As described above, the present invention can solve the nonuniformity of the surface of the color filter layer, such as similar or mura or residual film, by a reflow process by heat. In addition, the gap between the color filter layer and the photodiode can be narrowed due to the presence of the planarization film formed of BPSG serving as the protective film and the planarization layer. Therefore, since the color filter layer does not have to be large, the device can be made thin. In addition, since the number of photo processes is reduced as compared with the prior art, it is possible to reduce the damage of the substrate by the etching process, the thermal process and the strip.

Claims (6)

A color solid-state imaging device comprising: a semiconductor substrate, charge transfer regions formed at regular intervals on the semiconductor substrate, and photoelectric conversion regions formed between the charge transfer regions so as to be alternately arranged with the charge transfer regions on the semiconductor substrate; A microlens formed on the exposed substrate, a hemispherical shape on the planarization layer, a first to third color filter layers corresponding to the photoelectric conversion region, and covering the color filter layers; Color solid-state imaging device comprising a. The color solid-state imaging device of claim 1, wherein the planarization layer is formed of a Boro-Phospho Slicate Class (BPSG). The color solid slide device according to claim 1, wherein the microlilies are formed on the color filter layer in the same thickness. A method for manufacturing a color solid-state imaging device, comprising: forming charge transfer regions on a semiconductor substrate at predetermined intervals, and forming a photoelectric on the semiconductor substrate between the charge transfer regions so as to be alternately arranged with the charge transfer regions. Forming a conversion region, forming a planarization film on the exposed substrate, forming a color filter layer of the first to third colors corresponding to the photoelectric conversion region in a hemispherical shape on the planarization film; And forming a microlens covering the color filter layers. The method of claim 4, wherein the hemispherical color filter layer comprises the steps of: forming a resin layer on the planarization film, coloring the resin layer, patterning the colored resin layer in a predetermined shape, and A method of manufacturing a color solid-state imaging device, comprising forming a patterned colored resin layer by performing a heat reflow step and a hard baking step. The method of claim 4, wherein the microlens comprises forming a material layer for the microlens on the hemispherical color filter layer and the exposed planarization layer, and anisotropically etching the material layer for the microlens. And forming a color solid-state imaging device.