KR100790966B1 - CMOS image sensor having uniform photosensitivity per color filter - Google Patents

Abstract

A CMOS image device capable of securing uniform light sensitivity for each of R, G, and B color filters is disclosed. The disclosed CMOS image sensor includes a semiconductor substrate comprising a plurality of unit pixels composed of photodiodes and transistors. Inner lenses are formed on the semiconductor substrate so as to correspond to the photodiodes of the unit pixels, respectively, and R, G, and B color filters are arranged on the semiconductor substrate so as to correspond to the photodiodes and the inner lenses, respectively. In this case, the inner lens has a large aperture ratio and curvature in order of R, G, and B filters.

Light sensitivity, inner lens, color filter

Description

CMOS image sensor having uniform photosensitivity per color filter

1 is a circuit diagram schematically illustrating a unit pixel of a general CMOS image sensor.

2 is a plan view of a CMOS image sensor which integrally forms a molding part and a first metal wire defining an inner lens according to an embodiment of the present invention;

3 is a cross-sectional view of the CMOS image sensor taken along the line III-III ′ of FIG. 2.

4 is a plan view of a CMOS image sensor for separately forming a molding part and a first metal wire defining an inner lens according to another exemplary embodiment of the present invention;

FIG. 5 is a cross-sectional view of the CMOS image sensor taken along the line VV ′ of FIG. 4.

6 through 8 are cross-sectional views of a CMOS image sensor showing a molding having inclined sidewalls according to another embodiment of the present invention.

9 is a cross-sectional view of a CMOS image sensor with a landing pad according to another embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100 semiconductor substrate 115 transfer gate electrode
120: photodiode 125: floating diffusion region
140166: first metal wiring 145: flowable oxide film

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142a, 142b, 142c: molding part 150R, 150G, 150B: inner lens

The present invention relates to a complementary metal oxide semiconductor (CMOS) image sensor, and more particularly, to a CMOS image sensor having a uniform light sensitivity for each color filter.

CMOS image sensors are dominant in the field of solid-state imaging because they are easier to manufacture and can be produced at lower cost than charge coupled devices (CCDs). In addition, since the unit pixel of the CMOS image sensor is composed of MOS transistors, the unit pixel of the CMOS image sensor may be implemented in a smaller area than the CCD, thereby providing a high resolution. Furthermore, signal processing logic can be formed in the image circuit in which the pixels are formed, which has the advantage that the image circuit and the signal processing circuit can be integrated into one.

Such CMOS image sensors are composed of a plurality of unit pixels in order to realize high resolution. As shown in FIG. 1, each unit pixel stores a photodiode 15 for sensing light, a transfer transistor Tx for transferring charges generated by the photodiode 15, and the transferred charges. A reset transistor Rx that periodically resets the floating diffusion region FD and a source follower buffering a signal according to the charge charged in the floating diffusion region FD. source follower).

On the other hand, the CMOS image sensor includes a color filter to realize a color image. The color filter is composed of R (red), G (green), and B (blue) unit filters, and each unit filter is disposed to correspond to a unit diode, in particular, a photo diode of the unit pixel.

The R, G, B filter has a characteristic of absorbing only light of a specific wavelength. That is, the R filter absorbs light having a long wavelength of about 660 to 700 nm, the G filter absorbs light having a medium wavelength of 510 to 590 nm, and the B filter has light of short wavelength of 490 to 510 nm smaller than that of the R and G filters. Absorb. Accordingly, in the unit pixel (hereinafter, R filter region) in which the R filter is formed, electron hole recombination occurs deeply in the substrate (photo diode region) as the R filter absorbs light having a long wavelength. Accordingly, the light sensitivity is excellent because there is no missing electron hole.

However, the B filter, which absorbs light having a relatively short wavelength, has very low light sensitivity because recombination of electrons and holes occurs on the surface of the photodiode, that is, the p-type photodiode region. In other words, the p-type photodiode region formed on the surface of the substrate in the photodiode is provided to remove the dark source of the CMOS image sensor rather than the light sensing region as is known, in this case n Lower electron-hole recombination occurs in the photodiode region. Therefore, the light sensitivity is relatively low.

Accordingly, even if the unit pixels form the same condition, due to the difference in the light absorption rate (electron-hole recombination rate) of the filter, the light sensitivity of the unit pixel where the R filter is located and the light sensitivity of the unit pixel where the B filter are located Difference occurs. For this reason, there is a problem that the photosensitivity of the CMOS image sensor is also not uniform.

Accordingly, the technical problem to be achieved by the present invention is to provide a CMOS image device capable of securing uniform light sensitivity for each of R, G, and B filters.

In addition, the technical problem to be achieved by the present invention is to improve the light sensitivity of the B filter, to provide a CMOS image element having a uniform light sensitivity.

In order to achieve the above object of the present invention, the CMOS image sensor of the present invention includes a semiconductor substrate including a plurality of unit pixels composed of photodiodes and transistors. Inner lenses are formed on the semiconductor substrate so as to correspond to the photodiodes of the unit pixels, respectively, and R, G, and B color filters are arranged on the semiconductor substrate so as to correspond to the photodiodes and the inner lenses, respectively. In this case, the inner lens has a different aperture ratio and curvature for each color filter.

In addition, the CMOS image sensor according to another embodiment of the present invention includes a semiconductor substrate including a plurality of unit pixels composed of photodiodes and transistors. An interlayer insulating film is formed on the semiconductor substrate, and a metal part including a molding part formed to surround a photo diode for each unit pixel and a pattern for supplying an electrical signal to the transistor is formed on the interlayer insulating film. A flowable oxide film having a depression formed in a region corresponding to the photodiode is formed on the interlayer insulating film, an inner lens is formed on the depression, and the photodiode and the upper portion of the semiconductor substrate on which the inner lens is formed. Corresponding to the inner lens, an R, G, B color filter is formed which is arranged with a certain rule. The inner lens is formed such that the opening ratio and curvature of the R, G, and B filters are increased.

In addition, the CMOS image sensor according to another embodiment of the present invention includes a semiconductor substrate including a plurality of unit pixels composed of photodiodes and transistors. A first interlayer insulating film is formed on the semiconductor substrate, and a molding part is formed on the first interlayer insulating film to surround the photodiode for each unit pixel. A fluid oxide film having a depression defined by the molding portion is formed on the first interlayer insulating film, and an inner lens is formed in the depression. A second interlayer insulating film is formed on the semiconductor substrate including the inner lens, and a metal wiring is formed on the second interlayer insulating film so as to be electrically connected to the transistor. R, G, and B color filters are arranged on the semiconductor substrate on which the metal wiring is formed and correspond to the photodiode and the inner lens and have a predetermined rule. The inner lens is formed such that the opening ratio and curvature of the R, G, and B filters are increased.

The molding part is designed such that the area of the photodiode region exposed by the molding part is gradually increased in the order of the R, G, and B filters. The molding part may be a light blocking material having a melting point of 1000 ° C. or more, for example, one selected from a tungsten film, a titanium film, a titanium nitride film, and a laminate film of a titanium film and a titanium nitride film.

In addition, the molding part may have an inclined sidewall. The molding part may have a trapezoidal shape in cross section thereof, or may have a staircase slope formed by two patterns having different line widths. In addition, the molding part may form a spacer on the sidewall to implement the inclined sidewall.

The flowable oxide film may be a reflowed oxide film.

The metal wire is in electrical contact with the transistor and is formed in the first interlayer insulating film, a landing pad formed on the first stud, and a second interlayer insulating film formed in contact with the landing pad. The second stud may include a metal wiring pattern formed on the second interlayer insulating layer to contact the second stud.

At least one metal wiring for transmitting a signal between the metal wiring and the R, G, and B color filters may be further included, and the metal wirings may be disposed around the photodiode.

According to the present invention, by forming the aperture ratio and curvature of the inner lens in order of R, G, and B color filters, the light sensitivity of the B filter region can be relatively improved. On the other hand, even if the inner lens formed in the R filter region has a smaller aperture ratio and curvature than the inner lens formed in the B filter region, the R filter itself absorbs light having a long wavelength, thereby maintaining high light sensitivity. Accordingly, the light sensitivity of the CMOS image sensor can be made uniform.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in many different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape and the like of the elements in the drawings are exaggerated to emphasize a more clear description, and the elements denoted by the same reference numerals in the drawings means the same elements.

According to the present invention, the size of the inner lens of the unit pixel in which the B filter is to be disposed, that is, the aperture ratio and curvature of the inner lens is designed to be larger than the size (opening ratio and curvature) of the inner lens of the unit pixel in which the R filter and the G filter are to be disposed. It will increase the light sensitivity of the area. Preferably, the inner lens will be formed such that its aperture ratio and curvature increase in the order of R, G, and B color filters. Accordingly, the low light sensitivity of the B color filter is compensated by the size of the inner lens, thereby improving the light sensitivity of the overall CMOS image sensor.

In addition, the inner lens forms a molding portion to surround the photodiode and forms a reflowed oxide film thereon to form a region in which the inner lens is to be formed, and an insulating film having a different refractive index from the interlayer insulating film in the region where the inner lens is to be formed. Will form the inner lens. In addition, the size of the inner lens may be adjusted by the gap of the molding part, and this molding part may be formed on the same plane as the first metal wire, that is, at the same time. In addition, the molding part may be formed of a metal film, for example, a tungsten film, having heat resistance and light shielding properties.

Accordingly, the molding part does not melt during the reflow process of the flowable oxide film requiring high temperature, and the molding part having the light absorption characteristic is formed to surround the photodiode, thereby absorbing all light incident in a square without reflecting the upper wiring to the upper wiring to crosstalk. Will be reduced.

A CMOS image sensor having such characteristics will be described in more detail with reference to the accompanying drawings. FIG. 2 is a plan view of a CMOS image sensor according to an exemplary embodiment, and FIG. 3 is a cross-sectional view of the CMOS image sensor taken along line III-III ′.

As shown in FIGS. 2 and 3, the device isolation film 105 is formed on the semiconductor substrate 100 by a known shallow trench isolation (STI) method, whereby photodiode predetermined regions 101R, 101G, and 101B and transistor scheduled A plurality of active regions 103 formed of regions 102 are formed. In the figure, 101R is a photodiode predetermined region in which an R filter is to be disposed, 101G is a photodiode predetermined region in which a G filter is to be disposed thereafter, and 101B is a photodiode predetermined region in which a B filter is to be disposed later. In addition, the plurality of active regions all have the same size.

A gate insulating layer 110 and a conductive layer for a gate electrode, such as a doped polysilicon layer, are deposited on the semiconductor substrate 100 having the active region 103 defined therein. The gate electrode 115 of the transfer transistor (hereinafter referred to as a transfer gate electrode), the gate electrode 116 of the reset transistor (hereinafter referred to as a reset gate electrode), and the gate electrode 117 of the transistor forming a source follower by patterning the conductive layer for the gate electrode. Source follower gate electrode). The transfer gate electrode 115 may be positioned at a boundary between the photodiode predetermined regions 101R, 101G, and 101B and the transistor predetermined region 103, and the reset gate electrode 116 and the source follower gate electrode 117 may be Each may be located on the transistor predetermined region 103. Spacers 118 may be formed on sidewalls of the gate electrodes 115, 116, and 117 in a known manner.

The n-type photodiode region 121 is formed by ion implantation of n-type impurities into the photodiode predetermined regions 101R, 101G, and 101B. The p-type photodiode region 122 is formed by implanting p-type impurities into the photodiode predetermined regions 101R, 101G, and 101B, thereby completing the photodiode 120. In this case, the n-type photodiode region 121 is located deep in the substrate 100 to induce recombination of electrons and holes, and the p-type photodiode region 122 is positioned on the surface of the substrate 100 and may be dark on the surface of the substrate. Remove the dark source. The photodiode 120 may have the same size for each unit pixel.

Next, an n-type impurity is implanted into the transistor predetermined region 102 on the other side of the transfer gate electrode 115 to form a floating diffusion region 125. Simultaneously with forming the floating diffusion region 125, the source and drain regions 126 and the source and drain regions 127 and 128 of the transistors constituting the source follower may be formed together. In addition, in the present embodiment, the photodiode 120 is formed before the floating diffusion region 125, but the photodiode 120 may be formed after the floating diffusion region 125 is formed.

A first interlayer insulating layer 130, for example, a silicon oxide layer, is deposited on the semiconductor substrate 100 on which the photodiode and the transistors are formed to have a predetermined thickness. Subsequently, the first interlayer insulating layer 130 is etched to open the transfer gate electrode 115, the reset gate electrode 116, and the floating diffusion region 125 to form a contact hole 132. Next, the first conductive stud 135 is formed by filling the conductive layer in the contact hole 132. The first conductive stud 135 may be a conductive material such as a tungsten film or a doped polysilicon film having excellent interlayer embedding properties and excellent heat resistance. 3 is a cross-sectional view taken along line III-III ′ of FIG. 2, the contact portion of the floating diffusion region 125 should not be actually seen. However, the contact of the floating diffusion region 125 is provided for convenience of description. The site is shown.

The first metal wire 140 is formed on the first interlayer insulating layer 130 to be in contact with the exposed first conductive studs 135. The first metal wire 140 in this embodiment is in contact with the first conductive studs 135 to transfer a signal to the transfer gate electrode 115, the reset gate electrode 116, and the floating diffusion region 125. On the other hand, it is formed to surround the photodiode 120 to serve as a mold for building the inner lens region. In this case, the interval x1 between the mold portions of the unit pixels in which the B filter is to be disposed is greater than the interval x2 between the mold portions of the unit pixel in which the G filter is to be disposed and the interval x3 between the mold portions of the unit pixel in which the R Filter is to be placed. It is preferable that the first metal wiring 140 is formed so that the distance x2 between the mold portions of the unit pixel in which the G filter is to be disposed is larger than the distance x3 between the mold portions of the pixel in which the R filter is to be formed. Do. This is to provide an inner lens formation region having a large size in the order of R, G, and B filters.

On the other hand, the first metal wire 140 is preferably a metal film having excellent heat resistance with a melting point of 1000 ℃ or more, a conductive material having the ability to block (absorb) light, such as tungsten film (W), titanium film (Ti ), A titanium nitride film (TiN) or a laminated film (Ti / TiN) of a titanium film and a titanium nitride film is used as the metal wiring material. In addition, the first metal wire 140 may have a height of about 1500 to 2500 kV.

The flowable oxide film 145 is deposited on the first interlayer insulating film 130 on which the first metal wiring 140 is formed. As the flowable oxide film 145, for example, a borophosphorus silicate glass (BPSG) film, a phosphorus silicate glass (PSG) film, or a composite film (or a laminated film) of the BPSG film and the PSG film may be used. At this time, the thickness of the flowable oxide film 145 is directly connected to the curvature of the inner lens to be formed later. That is, the thinner the thickness of the flowable oxide film 145, the curvature of the inner lens is improved. If the thin film is formed too thin, the surface of the first metal wire 140 may be exposed. The thickness of the flowable oxide film 145 is determined in consideration of the covering of the 140.

Thereafter, the flowable oxide film 145 is heat treated at a temperature of 800 ° C. to 1000 ° C. to reflow. Then, the recessed portions 145R, 145G, and 145B are formed in the region corresponding to the photodiode 120 by the distance and height of the mold portion of the first metal wire 140. Additionally, the curvature of the depressions 145R, 145G, and 145B may be proportional to the reflow temperature. It is preferable to proceed the heat treatment at a higher temperature for a large curvature, but it is preferable to select appropriately within the above-mentioned temperature range in consideration of the performance of the transistor formed underneath.

On the other hand, since the spacing (size) of the mold 140 is set differently for each unit pixel, the sizes of the recesses 145R, 145G, and 145B are also different. That is, since the interval (x1, x2, x3) of the mold part is designed to increase in the order of R, G, B filters, the size of the recesses (145R, 145G, 145B) is also proportional to the interval (x1, x2, x3) of the molding part It is formed so as to increase sequentially.

In addition, in the present embodiment, since the first metal wire 140 is formed of a metal film having a melting point of 1000 ° C. or higher, the first metal wire 140 melts even when the high temperature reflow process is performed as described above. Does not occur.

Next, an insulating film for a lens is deposited on the flowable oxide film 145 having the recesses 145R, 145G, and 145B to sufficiently fill the recessed portion 145a. As the insulating film for a lens, an insulating film having a refractive index different from that of the silicon oxide film constituting the flowable oxide film 145 and the first interlayer insulating film 130 is preferably used. As the insulating film, for example, a silicon nitride film (SiN) or a silicon nitride oxide film (SiON) may be used. Thereafter, the surface of the lens insulating film is chemically mechanically polished by a predetermined thickness to form inner lenses 150R, 150G and 150B. In this case, the lens insulating film may be chemically mechanically polished to expose the surface of the first interlayer insulating film 130.

As the sizes of the depressions 145R, 145G and 145B are sequentially formed in order of R, G and B filters, the inner lenses 150R, 150G and 150B are formed in the depressions 145R, 145G and 145B. The size is also increased in the order of R, G, B filter. At this time, since the sizes of the inner lenses 150R, 150G and 150B are directly proportional to the aperture ratio and curvature of the inner lenses 150R, 150G and 150B, the aperture ratio and curvature of the inner lens 150B in the B filter area are relatively increased. . Accordingly, even in the B filter region absorbing light having a relatively short wavelength, a large amount of light can be captured by increasing the aperture ratio of the inner lens 150B, and the electron-hole inside the substrate 100 is improved by the curvature improvement. Recombination is induced to improve light sensitivity.

The second interlayer insulating layer 155 is deposited on the inner lens 150. Next, the via hole 156 is formed by etching the second interlayer insulating layer 155, the inner lens 150, and the flowable oxide layer 145 so that a predetermined portion of the first metal wire 140 is exposed. The second conductive stud 160 is formed in a known manner so that the via hole 156 is filled. As the second conductive stud 160, for example, a tungsten material having excellent interlayer embedding characteristics may be used. The second metal wire 165 is formed on the second interlayer insulating layer 155 to be in contact with the second conductive stud 160. As the second metal wire 165, a metal film having excellent conductivity, for example, an aluminum film Al or an aluminum alloy film, may be used. In this case, the first and second metal wires 140 and 165 may be located at the periphery of the photodiode 120 as is known. A third interlayer insulating layer 170 is formed on the second interlayer insulating layer 155 on which the second metal wiring 165 is formed. In this case, the third interlayer insulating layer 170 may be a planarization layer. Subsequently, a light blocking layer 175 is formed on the third interlayer insulating layer 170 to expose a portion of the photodiode 120. After filling the fourth interlayer insulating layer 180 between the light blocking layers 175, a first passivation layer 185 is formed on the light blocking layer 175 and the fourth interlayer insulating layer 180. Color filters 190R, 190G, and 190B are formed on the first passivation layer 185. In this case, the color filters 190R, 190G, and 190B are disposed to correspond to the photodiode 120, and the boundary portions of the color filters 190R, 190G, and 190B are formed on the light blocking layer 175. do. Thereafter, the second passivation layer 195 is formed on the color filters 190R, 190G, and 190B, and then the microlens 200 is formed on the second passivation layer 195. The microlens 200 is formed to correspond to the photodiode 120, respectively.

In the above embodiment, the mold part defining the inner lens area is integrally formed with the first metal wire 140, but the mold part defining the inner lens area may be formed separately from the first metal wire.

That is, as shown in FIG. 4 and FIG. 5, a light blocking film for forming a mold part is formed on the first interlayer insulating film 130 and then deposited on the first interlayer insulating film 130. The light blocking film may be a conductive film, and a film having a high melting point property having a melting point of 1000 ° C. or more, for example, a tungsten film, a titanium film, a titanium nitride film, or a titanium / titanium nitride film may be used. Next, the light blocking film is patterned to surround the edge portion of the photodiode 120 to form a mold part 142.

In this case, the mold unit 142 is designed such that the size of the photodiode 120 to be exposed by the mold unit 142 increases in the order of R, G, and B filters in the same manner as in the above-described embodiment. Next, a flowable oxide film 145, for example, a BPSG film, a PSG film, or a composite film (or a laminated film) of a BPSG film and a PSG film may be used on the mold part 142 and the first interlayer insulating film 130. Thereafter, the flowable oxide film 145 is heat treated at a temperature of 800 ° C. to 1000 ° C. to reflow. Accordingly, depressions 145R, 145G, and 145B, which are inner lens formation regions, are formed in the flowable oxide film 145. As described above, the depressions 145R, 145G, and 145B are sized by the height and spacing of the mold 142, and the size of the mold 142 is formed in the order of R, G, and B filters. Since the depressions 145R, 145G, and 145B are also large in order of the R, G, and B filters. In addition, since the mold part 142 is formed of a metal film having excellent heat resistance, such as a tungsten film, a titanium film, a titanium nitride film, or a titanium / titanium nitride film, its shape does not change even when a high temperature reflow process is performed.

An insulating film for a lens is deposited on the flowable oxide film 145. As the insulating film for a lens, a silicon nitride film or a silicon nitride oxide film having a different refractive index from the flowable oxide film 145 may be used. The insulating film for lenses is chemically mechanically polished to remain in the depressions 145R, 145G, and 145B to form inner lenses 150R, 150G, and 150B.

As the depressions 145R, 145G, and 145B are formed in different sizes according to R, G, and B filters, the inner lenses 150R, 150G, and 150B are also formed in the sizes of the depressions 145R, 145G, and 145B. Depending on the size. That is, the inner lenses 150R, 150G, and 150B are formed to have increasingly larger aperture ratios and curvatures in the order of R, G, and B color filters.

After depositing the second interlayer insulating film 155 on the inner lenses 150R, 150G, and 150B, predetermined portions of the floating diffusion region 125, the gate electrode 115 of the transfer transistor, and the gate electrode 116 of the reset transistor are formed. The second interlayer insulating layer 155, the fluid oxide layer 145, and the first interlayer insulating layer 130 are etched so as to expose the contact hole 158. The first conductive stud 161 is formed in a known manner so that the contact hole 158 is filled. As the first conductive stud 161, a tungsten metal film having excellent interlayer embedding characteristics and having light blocking characteristics may be used. A first metal wire 166 is formed on the flowable oxide film 145 to be in electrical contact with the first conductive stud 161. An aluminum film or an aluminum alloy film having excellent conductivity may be used as the first metal wire 166. Since the molding part 142 of the present exemplary embodiment is positioned in a plane different from that of the first metal wire 166, the molding part 142 may have more wiring margin than when the molding part and the metal wire are simultaneously formed. Accordingly, the molding part 142 may have a larger width than the first metal wire (140 in FIG. 3) surrounding the photodiode 120 in the embodiment.

A third interlayer insulating layer 171 is formed on the second interlayer insulating layer 155 on which the first metal wiring 166 is formed. The second metal wire 176 is formed on the third interlayer insulating layer 171 to be electrically connected to a predetermined portion of the first metal wire 166. In this case, the second metal wire 176 may also be used as an upper light blocking layer of the CMOS image device. In addition, the first and second metal wires 166 and 176 may be positioned outside the photodiode 120 so as not to affect the optical imaging of the photodiode. After forming the fourth interlayer insulating layer 180 between the second metal lines 176, the first protective layer 185, the R, G, and B color filters 190R, 190G, and 190B, and the second protective layer 195 are formed. And the micro lens 200 are sequentially formed.

On the other hand, when the molding part 142 defining the inner lenses 150R, 150G and 150B is formed separately from the first metal wires, the molding part may be improved to improve curvature of the inner lenses 150R, 150G and 150B. The side wall of the 142 may be formed to be inclined.

The molding portion 142a having the inclined sidewalls may be obtained by tapering etching the metal film as shown in FIG. 6. The molding part 142a obtained by the tapered etching has a trapezoidal cross section, and an inclination exists in the sidewall thereof, thereby improving curvature of the inner lenses 150R, 150G, and 150B.

In addition, as illustrated in FIG. 7, the molding part 142b may be formed of a multi-layered wiring having different line widths, and the sidewall thereof may have a stepped slope. In this case, the curvature of the inner lenses 150R, 150G, and 150B may be improved by the inclination of the molding part 142b.

In addition, as shown in FIG. 8, the spacer 143 may be formed on the sidewall of the molding part 142 having no sidewall inclination, thereby providing a slope on the sidewall of the molding part 142c. In this case, the spacer 143 may be formed of an insulating film having a refractive index different from that of the silicon oxide film, for example, a silicon nitride film.

In addition, when the molding part 142 has an inclined sidewall, the curvature of the inner lenses 150R, 150G, and 150B may be secured even if the reflow process is omitted.

On the other hand, when the molding part 142 and the first metal wiring are formed on different layers, the first conductive pad 161 may include the second interlayer insulating film 155, the inner lenses 150R, 150G, and 150B, and the flexible oxide film ( The contact failure may occur because it must be formed through the 145 and the first interlayer insulating layer 130. In order to solve this problem, a first stud 135 is formed in the first interlayer insulating film 130, and then a landing pad is formed to contact the first stud 135 on the first interlayer insulating film 130. 144 may be formed. The landing pad 144 is formed at the same time as the molding part 142 and is formed in a local island shape. Thereafter, a second stud 162 contacting the landing pad 144 is formed on the second interlayer insulating film 155, the inner lenses 150R, 150G, and 150B, and the flowable oxide film 145, and then, The first metal wire 166 is formed to contact the second stud 162.

Thus, by forming the landing pad 144 together with the molding part 142 between the first interlayer insulating film 130 and the flowable oxide film 145, a poor contact of the conductive pad (or contact stud) that is in contact with the first metal wiring. Can be prevented.

As described in detail above, according to the present invention, the aperture ratio and curvature of the inner lens are formed in order of R, G, and B color filters. Accordingly, it is possible to increase the amount of optical imaging of the B filter region which absorbs light of a relatively short wavelength and to induce electron and hole recombination deep in the substrate, thereby improving the light sensitivity of the B filter region relatively. On the other hand, even if the inner lens formed in the R filter region has a smaller aperture ratio and curvature than the inner lens formed in the B filter region, the R filter itself absorbs light having a long wavelength, thereby maintaining high light sensitivity. Accordingly, the light sensitivity of the CMOS image sensor can be made uniform.

In addition, the inner lens of this embodiment is formed in a molding portion surrounding the photodiode region and a depression formed in the reflowed oxide film formed thereon. At this time, the recessed portion, which is an inner lens formation region, is defined by the molding portion, and the molding portion is formed of a material having heat resistance and light blocking (absorption) characteristics.

Accordingly, since the shape of the molding part is not deformed during the reflow process of the oxide film for forming the recessed part, a desired inner lens area can be obtained, and the molding part itself does not reflect the light incident to the upper metal wiring toward the upper metal wiring. By blocking and absorbing, crosstalk with adjacent pixels can be prevented.

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. Do.

Claims (35)

A semiconductor substrate including a plurality of unit pixels composed of photo diodes and transistors; An inner lens formed on the semiconductor substrate to respectively correspond to the photodiode of the unit pixel; And It includes R, G, B color filters arranged with a predetermined rule on the semiconductor substrate so as to correspond to the photodiode and the inner lens, respectively, The inner lens has a different aperture ratio and curvature for each of the color filters, and the inner lens corresponding to the B color filter has a larger aperture ratio and larger curvature than the inner lens corresponding to the R and G color filters. The corresponding inner lens has a larger aperture ratio and larger curvature than the inner lens corresponding to the R color filter. delete delete delete A semiconductor substrate including a plurality of unit pixels composed of photo diodes and transistors; An inner lens formed on the semiconductor substrate to respectively correspond to the photodiode of the unit pixel; And It includes R, G, B color filters arranged with a predetermined rule on the semiconductor substrate so as to correspond to the photodiode and the inner lens, respectively, The inner lens has a different aperture ratio and curvature for each color filter, An interlayer insulating film formed over the semiconductor substrate and the inner lens, the molding part formed on the interlayer insulating film and surrounding the photodiode area to form the inner lens area, and the molding. And a flowable oxide film formed over the interlayer insulating film including the portion. The CMOS image sensor of claim 5, wherein the molding part is designed such that an area of a photodiode region exposed by the molding part is gradually increased in the order of the R, G, and B filters. 7. The CMOS image sensor of claim 6, wherein the molding part is a light shielding metal. The CMOS image sensor according to claim 7, wherein the molding part is one film selected from tungsten film, titanium film, titanium nitride film and a laminated film of titanium film and titanium nitride film. 6. The CMOS image sensor as claimed in claim 5, wherein the molding part is electrically floating. 6. The CMOS image sensor of claim 5, wherein the molding part is electrically connected. A semiconductor substrate including a plurality of unit pixels composed of photo diodes and transistors; An interlayer insulating film formed on the semiconductor substrate; A metal line formed on the interlayer insulating layer, the metal line including a molding part formed to surround a photodiode for each unit pixel and a pattern for supplying an electrical signal to the transistor; A flowable oxide film formed over the interlayer insulating film and having a depression defined by the molding part; Inner lenses respectively formed in the depressions; And And an R, G, and B color filter formed on the semiconductor substrate on which the inner lens is formed and arranged with a predetermined rule while corresponding to the photodiode and the inner lens. The inner lens is a CMOS image sensor, characterized in that formed in the order of R, G, B filter so that the aperture ratio and curvature increases. 12. The CMOS image sensor of claim 11, wherein the molding part is designed such that the area of the photodiode region exposed by the molding part is gradually increased in the order of the R, G, and B filters. The CMOS image sensor of claim 11, wherein the molding part is formed of a light blocking material having a melting point of 1000 ° C. or higher. 12. The CMOS image sensor of claim 11, wherein the molding part is one film selected from tungsten film, titanium film, titanium nitride film, and a laminated film of titanium film and titanium nitride film. 12. The CMOS image sensor of claim 11, wherein the flowable oxide film is a reflowed oxide film. The CMOS image sensor according to claim 15, wherein the flowable oxide film is a BPSG film, a PSG film, or a laminated film of a BPSG film and a PSG film. 12. The CMOS image sensor as claimed in claim 11, wherein the inner lens is formed on a surface of the flowable oxide film having the depression. 12. The CMOS image sensor of claim 11, wherein the inner lens is formed of an insulating film having a refractive index different from that of the interlayer insulating film. 19. The CMOS image sensor of claim 18, wherein the inner lens is formed of a silicon nitride film or a silicon nitride oxide film. 12. The apparatus of claim 11, further comprising at least one layer of metal wires for transmitting signals between the metal wires and the R, G, and B color filters, wherein the metal wires are disposed around the photodiode. CMOS image sensor. delete delete delete delete 12. The CMOS image sensor of claim 11, wherein the molding has an inclined sidewall. 26. The CMOS image sensor of claim 25, wherein the molding portion has a trapezoidal cross section. 27. The CMOS image sensor of claim 25, wherein the molding part is formed of two patterns having different line widths, and has a stepped slope.  27. The CMOS image sensor of claim 25, wherein the molding has spacers on the sidewalls. delete delete delete delete delete 12. The method of claim 11, further comprising an upper interlayer insulating film on the inner lens and the color filter, The metal wire may include: a first stud in electrical contact with the transistor and formed in the interlayer insulating film; a landing pad formed on the first stud; a second stud formed in the upper interlayer insulating film to contact the landing pad; And a metal wiring pattern formed on the upper interlayer insulating layer to contact the second stud. 12. The CMOS device of claim 11, further comprising at least one layer of metal lines for transmitting signals between the metal lines and the R, G, and B color filters, wherein the metal lines are disposed around the photodiode. Image sensor.

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