TWI595636B - Image sensor and process thereof - Google Patents

Description

Image sensor and its process

The present invention relates to an image sensor and a process thereof, and in particular to an image sensor and a process thereof, which have anti-reflection layers of different thicknesses corresponding to the respective color filters.

Since CMOS image sensors are fabricated based on complementary metal oxide semiconductor (CMOS) technology, CMOS image sensors fabricated using conventional CMOS circuit processes can integrate image sensors and their peripheral circuits. being widely used.

Conventional CMOS image sensors use Front Side Illumination (FSI) technology to fabricate pixels on a pixel array whose incident light passes through the front side of the pixel to reach the photo-sensing area (photo-sensing). Area). That is to say, the structure of the conventional front-illuminated CMOS image sensor is such that the incident light needs to pass through the dielectric layer and the metal layer before reaching the light sensing region, which leads to the tradition. CMOS image sensors face problems such as low quantum efficiency, severe cross talk between pixels, and dark current.

Another CMOS image sensor is a Back Side Illumination (BSI) CMOS image sensor. Because back-illuminated image sensors can also be integrated into traditional Semiconductor process manufacturing has the advantages of lower fabrication cost, smaller component size, and higher integration. In addition, the back-illuminated image sensor has the advantages of low operating voltage, low power consumption, high quantum efficiency, low-read-out noise, and random access as needed. Therefore, it has been widely used in electronic products such as PC cameras and digital cameras. Unlike the front-illuminated technology, the front end of the silicon die is constructed with an image sensor; the back-illuminated CMOS image sensor places a color filter and a microlens on the pixel. The back side causes incident light to enter the image sensor from the back of the image sensor. Compared to front-illuminated CMOS image sensors, this back-illuminated CMOS image sensor has several advantages: less light loss, lesser cross-interference, and better quantum efficiency.

A typical back-illuminated image sensor can be divided into a light sensing area and a peripheral circuit area according to its function, wherein the light sensing area is usually provided with a plurality of photodiodes arranged in an array, and respectively A MOS transistor with a reset transistor, a current source follower, and a row selector is used to receive external light and sense the intensity of the illumination, while the peripheral circuit area Used to connect internal metal interconnects and external connection lines. The photosensitive principle of the back-illuminated image sensor is to distinguish the incident light into a combination of light of different wavelengths, and then receive them by a plurality of photosensitive elements on the semiconductor substrate, and convert them into digital signals of different strengths and weaknesses. For example, the incident light is divided into a combination of three colors of red, blue, and green. It is then received by the corresponding photodiode and converted into a digital signal.

The invention provides an image sensor and a process thereof, which further improve the anti-reflection rate of the anti-reflection layer by forming an anti-reflection layer having different thicknesses, thereby improving the light transmittance of the image sensor and improving the specific color. Light sensing sensitivity.

The invention provides an image sensor comprising a plurality of color filters and an anti-reflection layer. The color filter is located on a substrate. The anti-reflection layer is located between the substrate and the color filter, and the anti-reflection layer corresponding to at least two of the color filters has different thicknesses.

The present invention provides an image sensing process comprising the following steps. First, an anti-reflection layer is formed on a substrate. Next, a plurality of color filters are formed on the anti-reflection layer, wherein the thickness of the anti-reflection layer of the portion directly under the at least two color filters is different.

Based on the above, the present invention provides an image sensor and a process thereof, which form an anti-reflection layer between a substrate and a color filter, and a portion of the anti-reflection layer corresponding to at least two of the color filters has Different thicknesses. Therefore, the antireflection layer of the present invention can have better antireflection than the antireflection layer having only a single thickness, thereby improving the light transmittance and the light sensing sensitivity of the specific color of the image sensor.

Figure 1-5 is a schematic cross-sectional view showing the image sensing process of the first embodiment of the present invention Figure. As shown in FIG. 1, an image sensing process front end process is performed, which may include the following steps. First, a substrate 110 is provided having a front surface S1 and a back surface S2. The substrate 110 is, for example, a substrate, a germanium-containing substrate, a tri-five-layer overlying substrate (eg, GaN-on-silicon), a graphene-on-silicon or a silicon-on-insulator (silicon- On-insulator, SOI) A semiconductor substrate such as a substrate. Then, a plurality of isolation structures 10 are formed on the front surface S1 of the substrate 110. The isolation structure 10 may be a shallow trench isolation structure, and may be formed by a shallow trench isolation process, but the invention is not limited thereto. Then, a plurality of photosensitive regions arranged in an array, such as photodiodes 22, 24, 26, to receive incident light, and at least one MOS transistor 40 may be formed between the isolation structures 10, which may be A MOS transistor such as a reset transistor, a current source follower, and a row selector is used to convert the sensed light into a digital signal or in a peripheral circuit region. The logic MOS transistor or the like is not exemplified in this embodiment. Then, a dielectric layer 120 is formed on the front surface S1 of the substrate 110. The dielectric layer 120 can be, for example, an interlayer dielectric layer, and can be an oxide layer, but the invention is not limited thereto. Thereafter, an etching process is performed to form a contact hole (not shown) in the dielectric layer 120, and a conductive material such as copper or tungsten is filled into a contact hole (not shown) to form at least one contact plug. 30. A gate 42 of the MOS transistor 40 and a source/drain 44 are connected, respectively. In order to simplify the present invention, the spirit of the present invention is clearly understood. In this embodiment, only three photodiodes 22, 24, 26 and a MOS transistor 40 are shown, but the photodiodes 22, 24, 26 and MOS are electrically The number of crystals 40 is not limited to this embodiment. In addition, the present invention may include other semiconductor components disposed on the substrate 110 and in the dielectric layer 120, such as Other interconnect structures (not shown) and the like may also be included in the dielectric layer 120, and the present embodiment is not exemplified.

Next, a multilayer inter-metal dielectric layer (IMD) 130 and a multi-layer metal layer 140 are formed. In detail, a multi-layer inter-metal dielectric layer (IMD) 130 may include a plurality of layers of patterned dielectric layers 132, 134, 136, 138 and a plurality of patterned metal layers 142, 144, 146. The process of forming the multi-layer inter-metal dielectric layer 130 and the multi-layer metal layer 140 may include: performing a deposition and planarization process to form a dielectric layer (not shown) on the interlayer dielectric layer 120; a patterned dielectric layer 132 is formed by an electrical layer (not shown); a metal (not shown) is filled in to form a metal layer 142 in the patterned dielectric layer 132; thereafter, the foregoing steps are repeated to form A stacked structure comprising a plurality of patterned dielectric layers 134, 136, 138 and a plurality of patterned patterned metal layers 144, 146. The patterned dielectric layer 132, 134, 136, 138 may be an oxide layer, and the patterned metal layer 142, 144, 146 may be a metal layer composed of a metal such as aluminum or copper, but the invention is not limited thereto. Then, an insulating layer 150 is formed to completely cover the plurality of metal interlayer dielectric layers 130 and the plurality of metal layers 140. The insulating layer 150 can be, for example, an oxide layer or a nitride layer, but the invention is not limited thereto.

Next, the formed structure is inverted, as shown in FIG. 1, and the insulating layer 150 is placed on a carrier wafer 50, and the substrate 110 is thinned from the back surface S2 of the substrate 110. Then, a doping process P1 is selectively performed on the back surface S2 of the substrate 110 to form a doping layer 160.

Then, as shown in Fig. 2, an oxide layer (not shown) is selectively formed on the doped layer 160, so that the dark current can be further reduced by reducing surface defects. Then, an anti-reflective layer 60' is formed on the doped layer 160 (or an oxide layer (not shown)), wherein the anti-reflective layer 60 has a top surface S3 and a bottom surface S4. The anti-reflective layer 60' may include a tantalum nitride (SiN) layer, a tantalum carbide (SiC) layer, a tantalum carbonitride (SiCN) layer, a niobium oxynitride (SiON) layer, an organic material layer, and the like. According to the light band passing through the anti-reflection layer 60', a material suitable for the anti-reflection layer 60' is selected to adjust the refractive index (RI) of the anti-reflection layer 60' required, but the present invention does not limit.

As shown in FIG. 3, a photoresist layer (not shown) is fully covered, and then a photoresist layer (not shown) is patterned to form a patterned photoresist layer K1, which exposes the photodiode. The anti-reflection layer 62 of the portion corresponding to the upper portion of 22. Next, an etching process P2 is performed to etch the exposed portion of the anti-reflective layer 62. Subsequently, the patterned photoresist layer K1 is removed, and as shown in FIG. 4, an anti-reflection layer 60 is formed, wherein the bottom surface S4 of the anti-reflection layer 60 is a flat surface, and a portion of the anti-reflection layer 62 is at the top. The surface is a concave surface with respect to the top surface of the anti-reflection layer 60 of other portions, so that the anti-reflection layer 60 has different thicknesses d1 and d2 corresponding to different photosensitive regions, and the thickness d2 is smaller than the thickness d1.

As shown in FIG. 5, a plurality of color filters 70 are sequentially formed on the anti-reflection layer 60. In this embodiment, three color filters 70 of blue, green, and red are formed on the anti-reflection layer 60; in other embodiments, other color filters of color or color may be formed, depending on the actual Need to be determined. Further, the color filters 70 are respectively one The blue filter 72, the green filter 74 and the red filter 76, and the thickness of the anti-reflection layer corresponding to each of the color filters 70 are respectively below the blue filter 72. The thickness d2 of the portion of the anti-reflection layer 62 is a quarter of the wavelength of the blue light, and the thickness d1 of the anti-reflection layers 64 and 66 located directly below the green filter 74 and the red filter 76 is between green light. One quarter of the wavelength between the wavelength and the wavelength of the red light. In this way, compared with directly forming an anti-reflection layer, the thickness thereof is a thickness d2 of a quarter of the blue light wavelength, and the embodiment can increase the anti-reflection rate of 5% in the green light band and the red light band. Furthermore, since the green light wavelength is closer to the red light wavelength than the blue light wavelength, the anti-reflection layers 64 and 66 of the portion directly below the green color filter 74 and the red color filter 76 are designed to be formed. A single thickness d1 is used to simplify the process steps and at the same time achieve the effect of improving the antireflection of the antireflection layer 60.

Further, in the present embodiment, the thickness d2 of the anti-reflection layer 62 of the portion directly below the blue filter 72 is designed to be one quarter of the blue wavelength, and is located at the green filter 74 and the red filter. The thickness d1 of the portions of the anti-reflective layers 64 and 66 directly below the 76 is designed to be one quarter of the wavelength between the wavelength of the green light and the wavelength of the red light; however, in other embodiments, the blue color can be filtered. The thickness d2 of the anti-reflection layer 62 directly under the sheet 72 is designed to be three-quarters or five-quarters of the blue wavelength, that is, one quarter of the wavelength plus n times the half wavelength (n is a positive integer) The thickness d1 of the anti-reflective layers 64 and 66 located directly below the green filter 74 and the red filter 76 is designed to be three-quarters of the wavelength between the green and red wavelengths. Or a quarter of a fifth, etc., that is, a quarter of the wavelength plus a half wavelength of n times (n is a positive integer), which also achieves the effects of the present invention. However, since the thinner anti-reflective layer 60 helps to increase light penetration Therefore, it is preferable to design the thickness of each portion of the anti-reflection layers 62, 64, 66 to be one quarter of each of the corresponding main penetration wavelengths.

In other embodiments, after forming the anti-reflective layer 60 having different thicknesses d1 and d2 as shown in FIG. 4, another etching process may be performed to further change the green filter 74 and the red filter 76. The thickness of the anti-reflection layer 60 is corresponding to further improve the anti-reflection rate of the anti-reflection layer 60.

6-8 are schematic cross-sectional views showing an image sensing process according to a second embodiment of the present invention. After the step of FIG. 4 is completed, as shown in FIG. 6, a photoresist layer (not shown) is comprehensively covered and a photoresist layer (not shown) is patterned to form a patterned photoresist layer. K2, which exposes the antireflection layers 62 and 64 corresponding to the portions above the photodiodes 22 and 24. Next, an etching process P3 is performed while etching the exposed portions of the anti-reflective layers 62 and 64. Subsequently, the patterned photoresist layer K2 is removed, and as shown in FIG. 7, an anti-reflection layer 60a is formed, wherein the bottom surface S4 of the anti-reflection layer 60a is a flat surface, and a part of the anti-reflection layers 62 and 64 are formed. The top surface is a concave surface with respect to a portion of the top surface of the anti-reflection layer 66, so that the anti-reflection layer 60a has different thicknesses d1, d2, and d3 corresponding to different photosensitive regions, and the thickness d3 is smaller than the thickness d2. The thickness d2 is again smaller than the thickness d1.

Further, the structure formed by the figures 3-4, 6-7 in the second embodiment can also be replaced by the figures 9-10. 9-10 are schematic cross-sectional views showing an image sensing process according to a third embodiment of the present invention. After the step of forming the anti-reflection layer 60' of Fig. 2, As shown in FIG. 9, a photoresist layer (not shown) is integrally covered and patterned with a photoresist layer (not shown) to form a patterned photoresist layer K3, which exposes the photodiode. The antireflection layers 62 and 64 corresponding to the upper portions of 22 and 24 are provided. Next, an etching process P4 is performed while etching the exposed portions of the anti-reflective layers 62 and 64. Then, the patterned photoresist layer K3 is removed. Continuing, as shown in FIG. 10, firstly covering a photoresist layer (not shown) and patterning a photoresist layer (not shown) to form a patterned photoresist layer K4, which exposes the photosensitive layer An anti-reflection layer 62 corresponding to a portion above the polar body 22. Next, an etching process P5 is performed to etch only the exposed portion of the anti-reflection layer 62. Then, the patterned photoresist layer K4 is removed. In this way, the structure as described in the second embodiment can also be formed. Of course, other processes may be applied to form the structure as described in the second embodiment, and will not be further described herein.

After the same structure is formed in the second embodiment or the third embodiment, as shown in Fig. 8, a plurality of color filters 70 are formed on the anti-reflection layer 60a. In this embodiment, three color filters 70 of blue, green, and red are formed on the anti-reflection layer 60a; in other embodiments, other color filters of color or color may be formed, depending on actual needs. And set. Furthermore, the color filters 70 are respectively a blue filter 72, a green filter 74 and a red filter 76, and the thickness of the anti-reflection layer corresponding to each of the color filters 70 is corresponding. Then, the thickness d3 of the anti-reflection layer 62 directly under the blue filter 72 is one quarter of the wavelength of the blue light, and the thickness d2 of the anti-reflection layer 64 located directly below the green filter 74 is A quarter of the wavelength of the green light, and a portion d1 of the anti-reflective layer 66 directly below the red filter 76 is one quarter of the wavelength of the red light. In this way, compared to directly forming an anti-reflection having a single thickness d3 The layer, by using the anti-reflection layer 60a of the present embodiment, can increase the anti-reflection rate of 5% in the green light band and the anti-reflection rate of 10% in the red light band.

Furthermore, in the present embodiment, the thickness d3 of the anti-reflection layer 62 directly under the blue color filter 72 is designed to be one quarter of the blue light wavelength, and the anti-reflection layer is located at a portion directly below the green color filter 74. The thickness d2 of 64 is designed to be one quarter of the wavelength of the green light, and the thickness d3 of the portion of the anti-reflection layer 66 directly below the red filter 76 is designed to be one quarter of the wavelength of the red light; but in other embodiments The thickness d3 of the anti-reflection layer 62 of the portion directly below the blue filter 72 can be designed to be three-quarters or five-quarters of the wavelength of the blue light, and the anti-reflection layer located in the portion directly below the green filter 74. The thickness d2 of 64 is designed to be three-quarters or five-quarters of the wavelength of the green light, and the thickness d1 of the anti-reflective layer 66 directly below the red filter 76 is designed to be three-quarters or four of the wavelength of the red light. In the fifth part, the effects described in the present invention can also be achieved. However, since the thin anti-reflective layer 60a helps to increase the penetration of light, the thickness of the anti-reflective layers 62, 64, 66 of each portion is designed to be the quarter of the wavelength of the main light transmitted by each portion. One is better.

Then, a flat layer (not shown) may be selectively formed on each of the color filters 70. Then, a microlens (not shown) is formed on each color filter 70 or a flat layer (not shown) to concentrate the light into each of the color filters 70. Thereafter, a passivation layer (not shown) may be selectively formed on each of the microlenses, and another semiconductor process such as a subsequent external electrical connection process may be followed. Thus, a back-illuminated complementary crystal image sensing device 100 is completed.

It is emphasized here that the thickness of the anti-reflection layers 62, 64, 66 located under portions of the respective color filters 70 is one quarter, four quarters of the wavelength of the light passing through the maximum intensity of each color filter 70. At three or five-quarters, the anti-reflective layers 62, 64, 66 of each portion may have an optimum anti-reflectivity; that is, the anti-reflection layer of the portion of the present invention by at least one color filter 70 The thickness of 62, 64, 66 is designed to pass through a quarter, three-quarters, or five-quarters of the maximum intensity of the color filter 70 to achieve better anti-reflectivity. Of course, the anti-reflective layers 60, 60a of the first, second, and third embodiments are formed into two or three different thicknesses, but in other embodiments, the anti-reflective layer may also have four or more thicknesses, depending on the color filter. The number of light sheets, the total class, and the specifications and performance of the actual image sensing device to be formed.

Furthermore, in one embodiment, the thickness d3 of the portion of the anti-reflective layer 62 directly below the blue color filter 72 is preferably 100/RIa +/- 15%; the resistance of the portion directly below the green filter 74 The thickness d2 of the reflective layer 64 is preferably 137.5 / RIb +/- 10%; the thickness d1 of the anti-reflective layer 66 directly under the red filter 76 is preferably 162.5 / RIc +/- 10%, wherein RIa, RIb and RIc refer to the refractive index (RI) of the antireflection layer at the wavelengths of blue light, green light and red light, respectively. For example, if the refractive index of the antireflective layer material is 3.5 at a wavelength of 400 nm, the thickness d3 is preferably (400 nm ^* 1/4) / 3.5 = 28.57 nm, and the anti-reflection The refractive index material has a refractive index of 2.4 at a wavelength of 550 nanometers (nm), and the thickness d2 is preferably (550 nm ^* 1/4) / 2.4 = 57.29 nm, and so on.

A method of forming the antireflection layers 60, 60a having different thicknesses according to the present invention The back-illuminated complementary crystal image sensing device 100 can increase the anti-reflection rate of the anti-reflection layer and improve the back-illuminated complementary crystal image sensing compared to the anti-reflection layer having only a single thickness. The light transmittance of the device 100 for a particular color and the light sensing sensitivity. In the first, second and third embodiments, an anti-reflection layer 60, 60a is formed, which has a top surface S3 and a bottom surface S4, and the bottom surface S4 is a flat surface and a part of the top surface S3 is A concave surface thus forms antireflection layers 60, 60a having different thicknesses. Hereinafter, a fourth embodiment is further provided, in which the anti-reflection layer has a structure in which the top surface is a flat surface and the bottom surface of the portion is a concave surface.

11-12 are schematic cross-sectional views showing an image sensing process according to a fourth embodiment of the present invention. First, the front end process of the present embodiment is the same as the process of the first drawing, but the doping process P1 may not be performed first in the process of the embodiment. Next, as shown in FIG. 11, the back surface S2 of the substrate 110 is etched to form at least one recess R1 and R2 in the substrate 110, and the substrate 110 having different thicknesses d4, d5, and d6 can be formed. A method of etching the anti-reflection layers 60, 60a is similar to the previous embodiment. For example, a patterned photoresist (not shown) may be exposed to expose only a portion of the substrate 112 and cover the other portions of the substrate, and then an etching process is performed to cause a portion of the substrate 112 to have a thickness d4. Then, a patterned photoresist (not shown) is exposed to expose only a portion of the substrate 114 and cover the other portions of the substrate, and then an etching process is performed to make the portion of the substrate 114 have a thickness d5. As such, a substrate 110 is formed having a thickness d4, d5, d6, wherein the thickness d6 is greater than the thickness d5, and the thickness d5 is again greater than the thickness d4. Of course, other structures can be formed by other etching steps.

Then, a doping process (not shown) is selectively performed, and as shown in FIG. 12, an anti-reflective layer 80 is overlaid on the substrate 110. The anti-reflective layer 80 may comprise a tantalum nitride (SiN) layer, a tantalum carbide (SiC) layer, a tantalum carbonitride (SiCN) layer, a niobium oxynitride (SiON) layer, and an organic material layer. In detail, an anti-reflection layer (not shown) may be completely covered on the substrate 110, and then the anti-reflection layer (not shown) may be selectively planarized to form the anti-reflection layer 80. In this way, the embodiment forms an anti-reflection layer 80 having a top surface S5 and a bottom surface S6, wherein the top surface S5 is a flat surface, and the bottom surface S6 of the partial anti-reflection layer is a concave surface, thereby The anti-reflective layer 80 has different thicknesses d7, d8, d9, and the thickness d7 is greater than the thickness d8, and the thickness d8 is greater than the thickness d9.

Thereafter, a plurality of color filters (not shown) may be further formed on the anti-reflection layer 80, and each of the color filters (not shown) respectively correspond to the respective photodiodes 22, 24, 26; Forming a flat layer (not shown) on each color filter (not shown); forming a microlens (not shown) on each color filter (not shown) or a flat layer (not shown) The light is concentrated on the color filters (not shown). Thereafter, a passivation layer (not shown) may be selectively formed on each of the microlenses, and another semiconductor process such as a subsequent external electrical connection process may be followed. As such, another back-illuminated complementary crystal image sensing device 200 can be formed.

Therefore, the embodiment also forms an anti-reflection layer 80 having different thicknesses, which corresponds to the maximum intensity of light that can pass through different color filters (not shown), thereby increasing the anti-reflection rate of the anti-reflection layer 80. Furthermore, the anti-reflection layer 80 of the embodiment is formed into three different thicknesses d7, d8, and d9, and in other embodiments, two or four types may be formed. The above thickness depends on the number of color filters, the total class, and the specifications and performance of the image sensing device to be formed. Furthermore, the relationship between the thickness of the anti-reflection layer 80 of the present embodiment and the color filters (not shown) and the achievable effects are similar to those of the anti-reflection layers 60, 60a and the color filters of the foregoing embodiments. The relationship between the light sheet 70 and the effect that can be achieved will not be described again.

In addition, the embodiments provided above are exemplified by forming the back-illuminated complementary crystal image sensing devices 100 and 200, but the present invention can also be applied to a Front Side Illumination (FSI) image sensor, etc. Other CMOS image sensors or Charge-Couple Devices (CCD). Moreover, the present invention can be widely applied to various devices using an anti-reflection layer, such as a liquid crystal on silicon (LCOS) or a liquid crystal display (LCD), etc., to increase The antireflection rate of the antireflection layer.

In summary, the present invention provides an image sensor and a process thereof, which form an anti-reflection layer between an anti-reflection layer and a color filter, and at least two of the color filters correspond to an anti-reflection layer. Have different thicknesses. Therefore, the present invention can have better anti-reflectance than the anti-reflection layer having only a single thickness, thereby improving the light transmittance and light sensing sensitivity of the image sensor for a specific color. More specifically, the anti-reflection layer having different thicknesses of the present invention has a top surface and a bottom surface, wherein the top surface is formed into a flat surface and a portion of the bottom surface is formed as a concave surface, or the bottom surface is formed into a The flat surface and a portion of the top surface are formed as a concave surface to form the desired different thickness of the anti-reflective layer. Furthermore, the anti-reflection layer is located at a portion directly below each color filter Preferably, the thickness is one quarter, three quarters or five quarters of the wavelength of the light passing through the maximum intensity of the color filter, in accordance with the present invention by antireflection of at least one color filter The thickness of the layer is designed to pass through a quarter, three-quarters or five-quarters of the wavelength of the maximum intensity of the color filter to achieve better anti-reflectivity.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

10‧‧‧Isolation structure

22, 24, 26‧‧‧Photosensitive diodes

30‧‧‧Contact plug

40‧‧‧MOS transistor

42‧‧‧ gate

44‧‧‧Source/Bungee

50‧‧‧ carrying wafer

60, 60', 60a, 60b, 80‧‧‧ anti-reflection layer

62, 64, 66‧‧‧ part of the anti-reflection layer

70‧‧‧Color filters

72‧‧‧Blue filter

74‧‧‧Green Filter

76‧‧‧Red Filter

100,200‧‧‧Back-illuminated complementary crystal image sensing device

110‧‧‧Base

Base of 112, 114‧‧‧

120‧‧‧ dielectric layer

130‧‧‧Multilayer metal interlayer dielectric layer

132, 134, 136, 138‧‧‧ patterned dielectric layers

140‧‧‧Multilayer metal layer

142, 144, 146‧‧‧ patterned metal layers

150‧‧‧Insulation

160‧‧‧Doped layer

D1, d2, d3, d4, d5, d6, d7, d8, d9‧‧ thickness

K1, K2, K3, K4‧‧‧ patterned photoresist layers

P1‧‧‧ doping process

P2, P3, P4, P5‧‧‧ etching process

R1, R2‧‧‧ grooves

S1‧‧ positive

S2‧‧‧Back

S3, S5‧‧‧ top surface

S4, S6‧‧‧ bottom

Figure 1-5 is a cross-sectional view showing the image sensing process of the first embodiment of the present invention.

6-8 are schematic cross-sectional views showing an image sensing process according to a second embodiment of the present invention.

9-10 are schematic cross-sectional views showing an image sensing process according to a third embodiment of the present invention.

11-12 are schematic cross-sectional views showing an image sensing process according to a fourth embodiment of the present invention.

10‧‧‧Isolation structure

22, 24, 26‧‧‧Photosensitive diodes

30‧‧‧Contact plug

40‧‧‧MOS transistor

42‧‧‧ gate

44‧‧‧Source/Bungee

50‧‧‧ carrying wafer

60a‧‧‧Anti-reflective layer

62, 64, 66‧‧‧ part of the anti-reflection layer

70‧‧‧Color filters

72‧‧‧Blue filter

74‧‧‧Green Filter

76‧‧‧Red Filter

100‧‧‧Back-illuminated complementary crystal image sensing device

110‧‧‧Base

120‧‧‧ dielectric layer

130‧‧‧Multilayer metal interlayer dielectric layer

132, 134, 136, 138‧‧‧ patterned dielectric layers

140‧‧‧Multilayer metal layer

142, 144, 146‧‧‧ patterned metal layers

150‧‧‧Insulation

160‧‧‧Doped layer

D1, d2, d3‧‧ thickness

S1‧‧ positive

S2‧‧‧Back

S3‧‧‧ top surface

S4‧‧‧ bottom

Claims (20)

An image sensor includes: a plurality of color filters on a substrate; and an anti-reflection layer between the substrate and the color filters and directly contacting the color filters, the color filters The anti-reflection layers corresponding to at least two of the light sheets have different thicknesses, and the bottom surfaces of the color filters are not coplanar. The image sensor according to claim 1, wherein the anti-reflection layer comprises a tantalum nitride (SiN) layer, a tantalum carbide (SiC) layer, a tantalum carbonitride (SiCN) layer, and a nitrogen. A layer of yttrium oxide (SiON). The image sensor of claim 1, wherein the anti-reflection layer has a top surface and a bottom surface. The image sensor of claim 3, wherein the top surface of the anti-reflection layer is a flat surface, and a portion of the bottom surface of the anti-reflection layer is a concave surface to make the anti-reflection layer different thickness of. The image sensor of claim 3, wherein the bottom surface of the anti-reflection layer is a flat surface, and a portion of the top surface of the anti-reflection layer is a concave surface to make the anti-reflection layer different. thickness of. The image sensor according to claim 1, wherein the color filter is corresponding to each The antireflection layer of a portion of the light sheet has a thickness which is one quarter, three quarters or five quarters of the wavelength of light that can pass the maximum intensity of the corresponding color filter. The image sensor of claim 6, wherein the color filters comprise a blue filter, a green filter, and a red filter. The image sensor of claim 7, wherein the anti-reflection layer at a portion directly under the blue filter has a thickness of one quarter of a blue wavelength and is located at the green filter. And the thickness of the anti-reflection layer at a portion directly under the red color filter is one quarter of a wavelength between the green light wavelength and the red light wavelength. The image sensor of claim 8, wherein the anti-reflection layer directly under the green filter has a thickness of one quarter of a green light wavelength and is located below the red color filter. The antireflection layer has a thickness of one quarter of the wavelength of the red light. The image sensor of claim 1, wherein the image sensor comprises a CMOS image sensor. The image sensor of claim 1, wherein the CMOS image sensor comprises a Back Side Illumination (BSI) image sensor or a Front Side Illumination (FSI) Image sensor. An image sensing process includes: forming an anti-reflection layer on a substrate; and forming a plurality of color filters directly on the anti-reflection layer and contacting the anti-reflection layer, wherein at least two of the color filters are The thickness of the anti-reflection layer in the portion directly below is different, and the bottom surfaces of the color filters are not coplanar. The image sensing process of claim 12, wherein the step of forming the anti-reflective layer comprises: covering an anti-reflective layer on the substrate; and etching the anti-reflective layer of the portion to make the anti-reflection The layers have at least two thicknesses. The image sensing process of claim 13, wherein the anti-reflective layer of the etched portion comprises one or more etching processes to form the anti-reflective layer having two or more thicknesses. The image sensing process of claim 12, wherein the step of forming the anti-reflective layer comprises: etching a portion of the substrate to form at least one recess in the substrate; and covering an anti-reflective layer On the substrate. The image sensing process of claim 12, wherein the anti-reflective layer comprises a tantalum nitride (SiN) layer, a tantalum carbide (SiC) layer, a tantalum carbonitride (SiCN) layer, and a nitrogen. A layer of yttrium oxide (SiON). The image sensing process of claim 12, wherein at least one portion of the anti-reflection layer directly under the color filter has a thickness, and the thickness is corresponding to the color filter. One-quarter, three-quarters, or five-quarters the wavelength of the light of maximum intensity. The image sensing process of claim 17, wherein the color filters comprise a blue filter, a green filter, and a red filter. The image sensing process of claim 18, wherein the anti-reflection layer at a portion directly under the blue filter has a thickness of one quarter of a blue wavelength and is located at the green filter. And the thickness of the anti-reflection layer at a portion directly under the red color filter is one quarter of a wavelength between the green light wavelength and the red light wavelength. The image sensing process of claim 19, wherein the anti-reflection layer at a portion directly under the green filter has a thickness of one quarter of a green wavelength and is located at the red filter. The thickness of the anti-reflection layer in the portion directly below is one quarter of the wavelength of the red light.