Title of Invention: IMAGE SENSOR AND METHOD FOR MANUFACTURING THE SAME

Technical Field

[I] This disclosure relates to an image sensor and a method of manufacturing the same. [2]

Background Art [3] An image sensor is a device including several million photoelectric conversion devices, and transfers light into an electric signal depending upon the light amount when receiving the light. The image sensor is applied to a digital input device that enables an image to be digitalized to transfer the digital image. Needs for various security devices and digital porters are exponentially increasing to correspond to the fast development in this generation. [4] The image sensor includes a pixel array in which a plurality of pixels are arranged in a matrix form, and each pixel includes a photo-sensing device and a transmitting and signal output device. The image sensor is broadly divided into a charge coupled device

(CCD) image sensor and a complementary metal oxide semiconductor (CMOS) image sensor depending upon the transmitting and signal output device. [5] The CMOS image sensor concentrates the outside light through a microlens, and the concentrated light is transmitted to the photo-sensing device such as a photodiode and the signal is output. [6] The CMOS image sensor is further refined to accomplish higher resolution, and recently research on decreasing the pixel size to \μm or less has been undertaken. [7]

Disclosure of Invention

Technical Problem [8] As the size of the microlens is also decreased according to reducing the pixel size, crosstalk to adjacent pixels is generated to deteriorate the resolution unless the focus distance of the lens is decreased.

Solution to Problem [9] One aspect of this disclosure provides an image sensor that prevents crosstalk to adjacent pixels and increases the resolution by improving photo-sensing efficiency. [10] Another aspect of this disclosure provides a method of manufacturing the image sensor.

[I I] According to one aspect of this disclosure, an image sensor is provided that includes a photo-sensing device, a color filter positioned on the photo-sensing device, a microlens positioned on the color filter, an insulation layer positioned between the photo-sensing device and the color filter and including a trench exposing the photo- sensing device, and a filler filled in the trench. The filler has light transmittance of about 85% or more at a visible ray region and a higher refractive index than the insulation layer.

[12] The filler has a 1.1 to 1.5 times higher refractive index than that of the insulation layer.

[13] The insulation layer may include silicon oxide, SiC, SiCOH, SiCO, SiOF, or a combination thereof.

[14] The filler may have a refractive index of about 1.6 to 1.85.

[15] The filler may be a polymer of a compound represented by the following Chemical

Formula 1.

[16] [Chemical Formula 1]

[18] In the above Chemical Formula 1, 3<n<190, Ri andR ₂ are selected from the group consisting of hydrogen, a substituted or unsubstituted Cl to ClO alkyl, a substituted or unsubstituted C3 to C 12 cycloalkyl, a substituted or unsubstituted C6 to C 12 aryl, a substituted or unsubstituted C3 to C 12 heteroaryl, and a combination thereof, and R ₃ is selected from the group consisting of a substituted or unsubstituted C2 to ClO alkylene, a substituted or unsubstituted C3 to C12 cycloalkylene, a substituted or unsubstituted C6 to C 12 arylene, a substituted or unsubstituted C3 to C 12 heteroarylene, and a combination thereof.

[19] The trench may have an aspect ratio of about 1.8 to about 4.

[20] The trench may have a width of about 0.8 to 1.2 times that of the photo-sensing device.

[21] According to another aspect of this disclosure, a method of manufacturing an image sensor is provided that includes providing a photo-sensing device, providing an insulation layer on the photo-sensing device, providing a trench in the insulation layer, filling the trench with a filler including a fluorene-based compound, providing a color filer on the insulation layer and the filler, and providing a microlens on the color filter.

[22] The fluorene-based compound may be represented by the above Chemical Formula

1, and has a molecular weight (Mw) of about 4000 to about 30,000.

[23] The filler may further include a cross-linking agent, an acid catalyst, and an organic solvent. [24] The method may further include curing the filler after filling the filler. The filler may have a refractive index of about 1.6 to about 1.85, and light transmittance of about 85% or more at a visible ray region.

[25]

Advantageous Effects of Invention

[26] The light concentrating efficiency is increased to prevent light leakage to an adjacent pixel. Accordingly, it is possible to provide an image sensor having high resolution and the light efficiency sensed to the photo-sensing device is increased.

[27]

Brief Description of Drawings

[28] FIG. 1 is a cross-sectional view of a CMOS image sensor according to one embodiment.

[29] FIG. 2 is a schematic diagram enlarging the "A" portion of the image sensor of FIG.

1.

[30] FIG. 3 is a cross-sectional view sequentially showing a process of manufacturing the

CMOS image sensor of FIG. 1.

[31]

Best Mode for Carrying out the Invention

[32] The present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of this disclosure are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of this disclosure.

[33] As used herein, when a definition is not otherwise provided, the term "substituted" refers to one substituted with a substituent selected from the group consisting of a halogen (F, Br, Cl, or I), a hydroxy, an alkoxy, a nitro, a cyano, an amino, an azido, an amidino, a hydrazino, a hydrazono, a carbonyl, a carbamyl, a thiol, an ester, a carboxyl, a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, an alkyl, a C2 to C16 alkenyl, a C2 to C16 alkynyl, an aryl, a C7 to C 13 arylalkyl, a Cl to C4 oxyalkyl, a Cl to C20 heteroalkyl, a C3 to C20 het- eroarylalkyl, a cycloalkyl, a C3 to C15 cycloalkenyl, a C6 to C15 cycloalkynyl, a hete- rocycloalkyl, and a combination thereof.

[34] As used herein, when a definition is not otherwise provided, the term " hetero" refers to one including 1 to 3 heteroatoms selected from the group consisting of N, O, S, and P.

[35] In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like elements throughout the speci- fication. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[36] Hereinafter, referring to FIG. 1, an image sensor according to one embodiment is described.

[37] FIG. 1 is a cross-sectional view of a CMOS image sensor according to one embodiment.

[38] In FIG. 1, a red pixel, a green pixel, and a blue pixel adjacent to each other are exemplary described, but are not limited thereto.

[39] Referring to FIG. 1, the photo-sensing device (PD) and transmitting transistor (not shown) are integrated on a semiconductor substrate 10. The photo-sensing device (PD) may include a photodiode. The photo-sensing device (PD) and the transmitting transistor are integrated in each pixel. As shown in the drawing, the photo-sensing device (PD) includes a photo-sensing device PDi of a red pixel, a photo-sensing device PD ₂ of a green pixel, and a photo-sensing device PD ₃ of a blue pixel. The photo- sensing device (PD) senses the light, and the sensed information by the photo-sensing device (PD) is transported the transmitting transistor.

[40] In addition, a metal line 21 and a pad 22 are formed on the substrate 10. The metal line 21 and the pad 22 may be made of a metal having a low resistivity such as aluminum (Al), copper (Cu), silver (Ag), and an alloy thereof to decrease the signal delay.

[41] A lower insulation layer 30 is formed on the metal line 21 and the pad 22. The lower insulation layer 30 may be made of an inorganic insulating material such as silicon oxide (SiO ₂ ), or a low dielectric constant (low-k) material such as SiC, SiCOH, SiCO, and SiOF.

[42] The lower insulation layer 30 has a trench 35 exposing each photo-sensing device PD i, PD ₂ , and PD ₃ of each pixel. The trench 35 is formed to provide an aspect ratio of 1.8 to 4, and for example, it may have a width of 0.5 to 0.8 μm and a height of about 1.5 to 2μm . The trench 35 is formed to provide a width of 0.8 to 1.2 times that of each photo- sensing device PD ₁ , PD ₂ , and PD ₃ of the pixel in order to prevent light crosstalk and to effectively sense light.

[43] A filler 40 is formed in the trench 35. The filler 40 includes a thick portion 40a filling each trench 40 and a thin portion 40b formed on the insulation layer 30. However, a thin portion 40b of the filler 40 may be removed depending upon the manufacturing method.

[44] The filler 40 has a higher refractive index than the insulation layer 30. Particularly, the filler 40 may have a refractive index of 1.1 to 1.5 times that of the insulation layer 30. For example, when the insulation layer 30 includes silicon oxide having a refractive index of 1.45 to 1.5, the filler 40 may have a refractive index of 1.6 to 1.85.

[45] The filler 40 has light transmission of 85% or more at a visible ray region.

[46] The filler 40 having the high refractive index and the high light transmission may include a fluorene-based compound.

[47] The fluorene-based compound may include a polymer of a compound represented by

Chemical Formula 1.

[48] [Chemical Formula 1]

[50] In the above Chemical Formula 1, 3<n<190, Ri andR ₂ are selected from the group consisting of hydrogen, a substituted or unsubstituted Cl to ClO alkyl, a substituted or unsubstituted C3 to C 12 cycloalkyl, a substituted or unsubstituted C6 to C 12 aryl, a substituted or unsubstituted C3 to C 12 heteroaryl, and a combination thereof, and R ₃ is selected from the group consisting of a substituted or unsubstituted C2 to ClO alkylene, a substituted or unsubstituted C3 to C12 cycloalkylene, a substituted or unsubstituted C6 to C 12 arylene, a substituted or unsubstituted C3 to C 12 heteroarylene, and a combination thereof.

[51] The filler may be prepared in a solution further including a cross-linking agent, an acid catalyst, and an organic solvent in addition to the fluorene-based compound. The solution may be cured by a method such as thermal curing to provide a filler having a high refractive index and transmission.

[52] A color filter 50 is positioned on the filler 40. The color filter 50 includes a red filter

50R formed on the red pixel, a green filter 50G formed on the green pixel, and a blue filter 50B formed on the blue pixel. The red filter 50R, the green filter 50G, and the blue filter 50B are respectively positioned on a photo-sensing device PD ₁ of a red pixel, a photo-sensing device PD ₂ of a green pixel, and a photo-sensing device PD ₃ of a blue pixel.

[53] An upper insulation layer 60 is formed on the color filter 50. The upper insulation layer 60 removes a step due to the color filter 50 and smoothes the same. The upper insulation layer 60 and the lower insulation layer 30 have a contact hole 65 exposing the pad 22.

[54] A microlens 70 is formed on the upper insulation layer 60 in the position corresponding to each color filter 50R, 50G, and 50B of the pixels. The microlens 70 con- centrates light coming from the outside.

[55] Referring to FIG. 2, the principal of the image sensor according to one embodiment of the present invention is schematically described.

[56] FIG. 2 is a schematic diagram enlarging the "A" portion of the image sensor of FIG.

1.

[57] The "A" portion of FIG. 1 refers to a unit cell of an image sensor.

[58] Referring to FIG. 2, the light concentrated from the microlens 70 is passed through the color filter 50 and then reflected several times in the trench 35 by total reflection, so it is gathered into a photo-sensing device (PD). The total reflection is generated by a refractive index difference between the filler 40 and the insulation layer 30. When the reflective index difference is increased, the total reflection is more effective.

[59] The light concentrated from the microlens 70 in the unit pixel is flowed into a photo- sensing device (PD) positioned in the pixel through the total reflection, so the light concentrating efficiency is increased to prevent light leakage to an adjacent pixel. Accordingly, it is possible to provide an image sensor having high resolution.

[60] Furthermore, it prevents the light loss by the filler 40 that is filled in the trench 35 and has high light transmittance of 85% or more, so the light efficiency sensed to the photo-sensing device is increased.

[61] The method of manufacturing the CMOS image sensor shown in FIG. 1 is described with reference to FIG. 3.

[62] FIG. 3 is a cross-sectional view sequentially showing a process of manufacturing the

CMOS image sensor of FIG. 1.

[63] First, a photo-sensing device (PD) is formed on each pixel of the semiconductor substrate 10 (Sl). The photo-sensing device (PD) may be formed in accordance with the generally well-known method including providing an impurity region, so a detailed description will be omitted.

[64] Then a metal layer is laminated on the semiconductor substrate 10 and subjected to photolithography to provide a metal line 21 and a pad 22 having a predetermined pattern (S2).

[65] Then a lower insulation layer 30 is formed on the front surface of the substrate (S3).

The lower insulation layer 30 may be formed in accordance with a method such as the chemical vapor deposition (CVD) or a solution process such as spin coating, slit coating, and InkJet printing.

[66] Subsequently, a trench 35 is formed on the lower insulation layer 30 to expose each photo-sensing device PDi, PD ₂ , and PD ₃ (S4). The trench 35 may be formed in accordance with the photolithography process.

[67] A filler is coated on the substrate (S5). The filler 40 may be formed as a solution.

[68] The filler 40 may include a fluorene-based compound. [69] The fluorene-based compound may include a compound represented by Chemical

Formula 1.

[70] [Chemical Formula 1]

[72] In the above Chemical Formula 1, 3<n<190, Ri andR ₂ are selected from the group consisting of hydrogen, a substituted or unsubstituted Cl to ClO alkyl, a substituted or unsubstituted C3 to C 12 cycloalkyl, a substituted or unsubstituted C6 to C 12 aryl, a substituted or unsubstituted C3 to C 12 heteroaryl, and a combination thereof, and R ₃ is selected from the group consisting of a substituted or unsubstituted C2 to ClO alkylene, a substituted or unsubstituted C3 to C12 cycloalkylene, a substituted or unsubstituted C6 to C 12 arylene, a substituted or unsubstituted C3 to C 12 heteroarylene, and a combination thereof.

[73] The fluorene-based compound may have a molecular weight (Mw) of about 4000 to about 30,000. When the molecular weight is within the above range, flatness and filling property of a film using the compound may be improved.

[74] The filler may further include a cross-linking agent, an acid catalyst, and an organic solvent besides the fluorene-based compound.

[75] The filler 40 has high light transmission of 85% or more as well as a high refractive index of 1.6 to 1.85. It is considered that the filler has substantially the same refractive index and light transmission both in the solution state and in the cured state. In addition, the filler has an excellent filling property regarding the trench having a high aspect ratio, so that it is efficiently filled into a fine trench so as to achieve good planarity. In addition, since the filler 40 has an excellent thermosetting property at a temperature of, for example, 200 to about 300 ⁰ C, it is beneficial to form a layer and has excellent chemical resistance. Thereby, it is possible to prevent degeneration caused by the chemicals that are used for forming other layers.

[76] The filler 40 may be coated in accordance with the solution process such as spin coating, slit coating, and InkJet printing.

[77] Then the coated filler 40 is thermally cured. The thermosetting process may be performed at 200 to 400 ⁰ C for 120 to 180 seconds.

[78] The cured filler 40 includes a thick portion 40a filled in the trench 35 and a thin portion 40b formed on the lower insulation layer 30. The thick portion 40a may be closely filled without voids, and the thin portion 40b may be smoothly formed on the surface thereof. Subsequently, the filler 40 and lower insulation layer 30 are partially removed to expose a pad 22 (S6). The filler 40 and the lower insulation layer 30 may be removed by wet etching.

[79] Then a pad protective layer 45 is formed on the front surface of the substrate (S7).

[80] Subsequently, the pad protective layer 45 is subjected to photolithography to leave a pad protective layer 45a only on the pad 22 and remove the other parts (S8).

[81] Each color filter 50R, 50G, and 50B is respectively formed on the filler 40 in a position corresponding to each photo-sensing device PD ₁ , PD ₂ , and PD ₃ (S9). The red filter 50R, the green filter 50G, and the blue filter 50B may be sequentially formed using an i-line stepper. However, the color filter 50R, 50G, and 50B may be formed by various methods, and the forming order is also changeable.

[82] Then an upper insulation layer 60 is formed on the front surface of substrate including color filter 50R, 50G, and 50B (SlO). The upper insulation layer 60 may be formed in accordance with a solution process such as spin coating, slit coating, and InkJet printing.

[83] A microlens 70 is formed on each color filter 50R, 50G, and 50B (S 11).

[84] Lastly, the upper insulation layer 60, the thin portion 40b of the filler 40, the lower insulation layer 30, and the pad protective layer 45a disposed on the pad 22 are removed to expose the pad 22 (S 12). Selectively, an ashing treatment may be carried out using oxygen gas (02).

[85]

Mode for the Invention

[86] Hereinafter, the embodiments are illustrated in more detail with reference to examples. However, the following are exemplary embodiments and are not limiting.

[87] <Synthesis of filler polymer>

[88] Synthesis Example 1

[89] 8.75 g (0.05 mol) of α,α'-dimethoxy-p-xylene, 26.66g of aluminum chloride, and 200 g of γ-butyrolactone were introduced into a If 4-neck flask mounted with a mechanical stirrer, a condenser, a 300ml dropping funnel, and a nitrogen gas -introduction tube with inflowing nitrogen gas, and sufficiently stirred. After 10 minutes, a solution in which 35.03 g (0.10 mol) of 4,4'-(9-fluorenylidene)diphenol was dissolved in 200 g of γ-butyrolactone was slowly dripped for 30 minutes and reacted for 12 hours. After completing the reaction, the acid was removed using water and condensed by an evaporator. Then it was diluted using methylamylketone (MAK) and methanol to provide a solution of MAK/methanol=4/l (weight ratio) in a concentration of 15 wt%. The solution was introduced into a 31 separate funnel and added with n-heptane to remove a low molecular body including a monomer. Thereby, it provided a polymer (Mw= 10,000, polydispersity=2.0) represented by the following Chemical Formula IA. [90] [Chemical Formula IA]

[92] Synthesis Example 2 [93] A polymer (Mw=7600) represented by the following Chemical Formula IB was prepared in accordance with the same procedure as in Synthesis Example 1, except that formaldehyde was used instead of α,α'-dimethoxy-p-xylene.

[94] [Chemical Formula IB]

[96] Synthesis Example 3 [97] A polymer (Mw=5000) represented by the following Chemical Formula 1C was prepared in accordance with the same procedure as in Synthesis Example 1, except that benzaldehyde was used instead of α,α'-dimethoxy-p-xylene.

[98] [Chemical Formula 1C]

[100] Synthesis Example 4 [101] A polymer (Mw=5800) represented by the following Chemical Formula ID was prepared in accordance with the same procedure as in Synthesis Example 1, except that 4-hydroxybenzaldehyde was used instead of α,α'-dimethoxy-p-xylene.

[102] [Chemical Formula ID]

[104] Synthesis Example 5

[105] A polymer (Mw=4300) represented by the following Chemical Formula IE was prepared in accordance with the same procedure as in Synthesis Example 1, except that α,α'-dimethoxy-p-biphenyl was used instead of α,α'-dimethoxy-p-xylene. [106] [Chemical Formula IE]

[108] Comparative Synthesis Example 1 [109] 50 g (0.17 mol) of 4,4'-oxydiphthalicanhydride, 28.35 g (0.14 mol) of 4,4'-diaminodiphenylether, and 6.8 g (0.04 mol) of norborene-

2,3-dicarboxylicanhydride were introduced into a 1£ 4-neck flask mounted with a mechanical stirrer, a condenser, a 300ml dropping funnel, and a nitrogen gas -introduction tube with inflowing nitrogen gas, and mixed with 700 g of an NMP solvent and stirred. It was heated to 8O ⁰ C and agitated for 3 hours to carry out the reaction. After carrying out the reaction for 3 hours and dripping the NMP reaction solution in 71 of water for one hour, it was agitated for 30 minutes and filtered with a Buchner funnel to provide a polyimide (Mw=10,000, polydispersity=2.1).

[HO] The polymers obtained from Synthesis Examples 1 to 5 and Comparative Synthesis Example 1 were measured to determine the refractive index and transmission. The refractive index was measured at 633 nm, and the transmission was measured at a visible ray region of 400 to 800 nm. The refractive index and light transmission of the polymer are considered as substantially the same in both the solution and cured states.

[111] The results are shown in Table 1. [112] Table 1 [Table 1] [Table ]

[113] As shown in Table 1, the polymers obtained from Synthesis Examples 1 to 5 had a high refractive index of 1.6 or more and high transmission of 85% or more. On the other hand, the polyimide compound according to Comparative Synthesis Example 1 had lower transmission than that of Synthesis Examples 1 to 5.

[114] <Manuf acturing Filler >

[115] A filler was prepared as in the following Examples 1 to 11 using the polymers represented by Chemical Formula IA to Chemical Formula IE obtained from Synthesis Examples 1 to 5.

[116] Example 1

[117] 1.0 g of the polymer (Mw=10,000) represented by Chemical Formula IA obtained from Syntheses Example 1 was weighed, and 0.05 g of a cross-linking agent (L- 145, manufactured by CYTEC) represented by the following Chemical Formula 2 and 0.01 g of pyridinium p-toluene sulfonate were added and dissolved in 8 g of propylene glycol monomethyl ether acetate (PGMEA) and filtered to provide a filler.

[118] [Chemical Formula 2]

[119] H H

HCl M _^ >L N _^ OH

HN OH

[120] Example 2

[121] A filler was prepared in accordance with the same procedure as in Example 1, except that the polymer (Mw=5000) represented by Chemical Formula IA having the different molecular weight was used instead of the polymer of Example 1.

[122] Example 3

[123] A filler was prepared in accordance with the same procedure as in Example 1, except that the cross-linking agent (Powderlink 1174, manufactured by CYTEC) represented by the following Chemical Formula 3 was used instead of the cross-linking agent represented by Chemical Formula 2.

[124] [Chemical Formula 3]

[126] Example 4

[127] A filler was prepared in accordance with the same procedure as in Example 1, except that the cross-linking agent was not used.

[128] Example 5

[129] A filler was prepared in accordance with the same procedure as in Example 1, except that the polymer (Mw=7600) represented by Chemical Formula IB obtained from Synthesis Example 2 was used instead of the polymer obtained from Synthesis Example 1.

[130] Example 6

[131] A filler was prepared in accordance with the same procedure as in Example 5, except that the polymer (Mw=22,000) represented by Chemical Formula IB having a different molecular weight was used instead of the polymer of Example 5.

[132] Example 7

[133] A filler was prepared in accordance with the same procedure as in Example 1, except that the polymer (Mw=5000) represented by Chemical Formula 1C obtained from Synthesis Example 3 was used instead of the polymer obtained from Synthesis Example 1.

[134] Example 8

[135] A filler was prepared in accordance with the same procedure as in Example 7, except that the polymer (Mw=I 1,000) represented by Chemical Formula 1C having a different molecular weight was used instead of the polymer of Example 7.

[136] Example 9

[137] A filler was prepared in accordance with the same procedure as in Example 1, except that the polymer (Mw=5800) represented by Chemical Formula ID obtained from Synthesis Example 4 was used instead of the polymer obtained from Synthesis Example 1.

[138] Example 10

[139] A filler was prepared in accordance with the same procedure as in Example 9, except that the polymer (Mw=12,500) represented by Chemical Formula ID having a different molecular weight was used instead of the polymer of Example 9.

[140] Example 11

[141] A filler was prepared in accordance with the same procedure as in Example 1, except that the polymer (Mw=4300) represented by Chemical Formula IE obtained from Synthesis Example 5 was used instead of the polymer obtained from Synthesis Example 1.

[142] Comparative Example 1

[143] A filler was prepared in accordance with the same procedure as in Example 1, except that the polymer (Mw= 10,000) obtained from Comparative Synthesis Example 1 was used.

[144] <Evaluation 1>

[145] Each filler obtained from Examples 1 to 11 was coated on a wafer for a CMOS image sensor formed with a 0.8/M X 2.0/M trench in accordance with a spin coating method and cured at 200 ⁰ C for 5 minutes.

[146] The filler was measured for trench filling property, film planarity, and chemical resistance. The trench filling property and film planarity were measured using a scanning electron microscope (SEM), and the chemical resistance was measured by dipping the wafer into each of trimethylammonium hydroxide (TMAH) (2.35%), isopropyl alcohol (IPA), propylene glycol monomethylether acetate (PGMEA), and acetone for one minute, and the thickness change was measured using KST4000-DLX(manufactured by KMAC). The results are shown in Table 2.

[147] Table 2 [Table 2] [Table ]

[148] In Table 2, for rating the trench filling property, © indicates that all the trench was well filled, O indicates that the trench was partially not filled, and x indicates that none of the trench was filled. For rating the film planarity, the film surface step was measured by using an atomic force microscope (AFM), and © indicates having a step of 100 nm or less, O indicates having a step of 100 nm to \μm , and x indicates having a step of 1 μm or more.

[149] As shown in Table 2, it is understood that when the layer is made using the filler according to the exemplary embodiment of the present invention, it is possible to provide good characteristics such as trench filling property, film planarity, and chemical resistance. On the other hand, when the layer is made using polyimide, the trench filling property and film are poor, and the chemical resistance to each solvent is deteriorated.

[150] <Evaluation 2> [151] A CMOS image sensor including a plurality of pixels having a size of about 1.4/M was fabricated in accordance with the same method as in the above embodiment. It included the filler obtained in each of Examples 1, 3, 5, 7, 9, and 11 and Comparative Example 1. In addition, as Comparative Example 2, the conventional CMOS image sensor formed with no trench or filler was fabricated.

[152] The obtained CMOS image sensors were measured to determine the luminance of unit pixels using T-10M illuminometer (manufactured by Konica-Minolta Co. Ltd.).

[153] The results are shown in Table 3. [154] Table 3 [Table 3] [Table ]

[155] As shown in Table 3, it is confirmed that when the trench is formed on the photosensitive device of the CMOS image sensor and the trench is filled with a filler according to an exemplary embodiment, the light amount inflow into each pixel is increased compared to the case of Comparative Example 1 including a filler of polyimide and the case of Comparative Example 2 including no trench or filler. It is also confirmed that the concentrated light from the microlens is flowed into the corresponding light sensing device through the filler having a high refractive index and a high transmission according to the exemplary embodiments of the present invention, so as to increase the light efficiency. This means that the light efficiency sensed by the photo-sensing device of the corresponding pixel is increased to improve the light efficiency of the CMOS image sensor. [156] While this disclosure has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[157]