TWI756006B - Image sensor and manufacturing method thereof - Google Patents

Abstract

An image sensor including a substrate, a first light sensing device, a dielectric layer, and a first light shielding structure is provided. The substrate includes a first region. The substrate has a first trench located in the first region. The first light sensing device is located in the substrate of the first region. The first trench is located at the side of the first light sensing device. The dielectric layer is disposed on the substrate and filled in the first trench. The first light shielding structure is located above the first light sensing device. There is a first opening between the adjacent first light shielding structures. The first light shielding structure includes a first light shielding layer and a first light shielding wall. The first light shielding layer is disposed on the dielectric layer. The first light shielding wall is connected to the first light shielding layer and extends along a direction toward the substrate. The first opening is located between the first light shielding walls of the adjacent first light shielding structures.

Description

Image sensor and method of making the same

The present invention relates to a semiconductor structure and a manufacturing method thereof, and more particularly, to an image sensor and a manufacturing method thereof.

Many modern electronic devices (eg, smart phones, digital cameras, biomedical imaging devices or automated imaging devices, etc.) include image sensors. Some image sensors (eg, backside illuminated image sensor, BSI image sensor) include a black level calibration (BLC) area, which is shielded by an entire light-shielding layer The photosensitive element located in the black level calibration area to avoid the light hitting the photosensitive element in the black level calibration. However, in the subsequent hydrogen sintering (H ₂ sintering) process, since the entire light-shielding layer will prevent the gas remaining in the deep trench isolation (DTI) from being outgassed, the image quality will be reduced. The electrical performance of the tester.

The present invention provides an image sensor and a manufacturing method thereof, which can be exhausted smoothly, thereby improving the electrical performance of the image sensor.

The present invention provides an image sensor including a substrate, a first photosensitive element, a dielectric layer and a first light shielding structure. The substrate includes a first region. The substrate has a first trench in the first region. The first photosensitive element is located in the substrate of the first region. The first trench is located at the side of the first photosensitive element. The dielectric layer is disposed on the substrate and fills the first trench. The first light shielding structure is located above the first photosensitive element. There are first openings between adjacent first light-shielding structures. The first light-shielding structure includes a first light-shielding layer and a first light-shielding wall. The first light shielding layer is disposed on the dielectric layer. The first light-shielding wall is connected to the first light-shielding layer and extends along the direction toward the substrate. The first openings are located between the first light-shielding walls of the adjacent first light-shielding structures.

According to an embodiment of the present invention, in the above-mentioned image sensor, the first opening may be located above the first trench.

According to an embodiment of the present invention, in the above-mentioned image sensor, the width of the first opening may be smaller than the width of the first trench.

According to an embodiment of the present invention, in the above-mentioned image sensor, the width of the first opening may be 50% to 75% of the width of the first trench.

According to an embodiment of the present invention, in the above-mentioned image sensor, the width of the first light-shielding wall may be 25% to 50% of the width of the first trench.

According to an embodiment of the present invention, in the above-mentioned image sensor, the direction toward the substrate may be perpendicular to the top surface of the substrate.

According to an embodiment of the present invention, in the above-mentioned image sensor, the top-view shape of the first light-shielding wall can be a rectangular ring.

According to an embodiment of the present invention, in the above-mentioned image sensor, the first light-shielding layer and the first light-shielding wall may be independent components.

According to an embodiment of the present invention, in the above-mentioned image sensor, the first light shielding layer and the first light shielding wall can be integrally formed.

According to an embodiment of the present invention, in the above-mentioned image sensor, the first light shielding layer may be located above the first photosensitive element.

According to an embodiment of the present invention, in the above-mentioned image sensor, the substrate may further include a second region. The substrate may have a second trench in the second region. A dielectric layer may fill the second trenches. The image sensor may further include a second photosensitive element and a second light shielding structure. The second photosensitive element is located in the substrate of the second region. The second trench is located on the side of the second photosensitive element. The second light shielding structure is located above the second trench. The second light shielding structure may include a second light shielding layer. The second light shielding layer is disposed on the dielectric layer.

According to an embodiment of the present invention, in the above-mentioned image sensor, the second light-shielding structure may further include a second light-shielding wall. The second light-shielding wall is connected to the second light-shielding layer and extends along the direction toward the substrate. The second light-shielding structure may have a second opening penetrating the second light-shielding structure. The second opening may be located above the second photosensitive element.

According to an embodiment of the present invention, the above-mentioned image sensor may further include a high-k dielectric layer. A high-k dielectric layer is disposed between the dielectric layer and the substrate.

The present invention provides a manufacturing method of an image sensor, which includes the following steps. Provide a base. The substrate includes a first region. A first photosensitive element is formed in the substrate of the first region. A first trench is formed in the base of the first region. The first trench is located at the side of the first photosensitive element. A dielectric layer is formed on the substrate. The dielectric layer fills the first trench. A first light shielding structure is formed above the first photosensitive element. There are first openings between adjacent first light-shielding structures. The first light-shielding structure includes a first light-shielding layer and a first light-shielding wall. The first light shielding layer is disposed on the dielectric layer. The first light-shielding wall is connected to the first light-shielding layer and extends along the direction toward the substrate. The first opening is located above the first trench.

According to an embodiment of the present invention, in the above-mentioned manufacturing method of the image sensor, the method for forming the first light shielding structure may include the following steps. A first light shielding layer is formed on the dielectric layer of the first region. A capping layer covering the first light shielding layer is formed. A second opening is formed in the cap layer and the first light shielding layer. A light-shielding material layer is conformally formed on the surface of the second opening. The light-shielding material layer is etched back to expose the dielectric layer and the cap layer, and form a first light-shielding wall.

According to an embodiment of the present invention, in the above-mentioned manufacturing method of the image sensor, the substrate may further include a second region. The manufacturing method of the image sensor may further include the following steps. A second photosensitive element is formed in the substrate of the second region. A second trench is formed in the base of the second region. The second trench is located on the side of the second photosensitive element. A dielectric layer is formed on the substrate. The dielectric layer fills the second trench. A second light shielding layer is formed on the dielectric layer of the second region. The second light shielding layer may be located above the second trench.

According to an embodiment of the present invention, in the above-mentioned manufacturing method of the image sensor, the method for forming the first light shielding structure may include the following steps. A first groove is formed in the dielectric layer of the first region. A light-shielding material layer filled in the first groove is formed on the dielectric layer. The light-shielding material layer is patterned to form a first light-shielding structure above the first photosensitive element.

According to an embodiment of the present invention, in the above-mentioned manufacturing method of the image sensor, the top-view shape of the first groove may be a rectangular ring.

According to an embodiment of the present invention, in the above-mentioned manufacturing method of the image sensor, the substrate may further include a second region. The manufacturing method of the image sensor may further include the following steps. A second photosensitive element is formed in the substrate of the second region. A second trench is formed in the base of the second region. The second trench is located on the side of the second photosensitive element. A dielectric layer is formed on the substrate. The dielectric layer fills the second trench. A second groove is formed in the dielectric layer of the second region. A light-shielding material layer filled in the second groove is formed on the dielectric layer. The light-shielding material layer is patterned to form a second light-shielding structure above the second trench. The second light-shielding structure may include a second light-shielding layer and a second light-shielding wall. The second light shielding layer is disposed on the dielectric layer. The second light-shielding wall is connected to the second light-shielding layer and extends along the direction toward the substrate.

According to an embodiment of the present invention, the above-mentioned manufacturing method of the image sensor may further include the following steps. After forming the first trench and before forming the dielectric layer, a high-k dielectric layer is formed on the substrate.

Based on the above, in the image sensor and its manufacturing method proposed by the present invention, since the first light-shielding structures are located in the first region, and there are first openings between adjacent first light-shielding structures, the subsequent hydrogen sintering During the processing, the gas remaining in the deep trench isolation structure can be smoothly exhausted from the first opening, thereby improving the electrical performance of the image sensor. In addition, since the first light-shielding wall is connected to the first light-shielding layer and extends in the direction toward the substrate, light can be blocked by the first light-shielding layer and the first light-shielding wall to prevent the light from being irradiated in the first area. the first photosensitive element.

In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, the following embodiments are given and described in detail with the accompanying drawings as follows.

1A to 1G are cross-sectional views illustrating a manufacturing process of an image sensor according to an embodiment of the present invention. FIG. 2 is a top view of the light-shielding wall and the photosensitive element in FIG. 1F .

Referring to FIG. 1A , a substrate 100 is provided. The substrate 100 may include the first region R1. The first region R1 may be a black level calibration (BLC) region. In addition, the substrate 100 may further include the second region R2. The second region R2 may be a pixel region. The substrate 100 may have a first surface S1 and a second surface S2 opposite to each other. The substrate 100 can be a semiconductor substrate, such as a silicon substrate such as an epitaxial silicon substrate, but the invention is not limited thereto.

Next, the photosensitive element 102 may be formed in the substrate 100 of the first region R1, and the photosensitive element 104 may be formed in the substrate 100 of the second region R2. The photosensitive element 102 and the photosensitive element 104 may be adjacent to the first surface S1 of the substrate 100 . The photosensitive element 102 and the photosensitive element 104 are, for example, photodiodes. The formation method of the photosensitive element 102 and the photosensitive element 104 is, for example, an ion implantation method.

In addition, required semiconductor elements (not shown), such as transistors, dielectric layers or interconnect structures, etc., can be formed on the first surface S1 of the substrate 100 , and the description thereof is omitted here.

In some embodiments, the substrate 100 may be disposed on the carrier substrate 106 . The carrier substrate 106 may be a semiconductor substrate, such as a silicon substrate, but the invention is not limited thereto.

Next, a trench T1 may be formed in the substrate 100 of the first region R1, and a trench T2 may be formed in the substrate 100 of the second region R2. The trench T1 is located on the side of the photosensitive element 102 . The trench T2 is located on the side of the photosensitive element 104 . The trenches T1 and T2 may be deep trenches. The trench T1 and the trench T2 are formed by, for example, patterning the second surface S2 of the substrate 100 through a lithography process and an etching process.

Referring to FIG. 1B , a high-k dielectric layer 108 may be formed on the substrate 100 . The high-k dielectric layer 108 can be used to limit the movement paths of electrons to prevent electrons from being freed between adjacent photosensitive elements (eg, between adjacent photosensitive elements 102 or between adjacent photosensitive elements 104 ). interference caused by movement. The material of the high-k dielectric layer 108 is, for example, tantalum oxide (Ta ₂ O ₅ ), aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), titanium oxide (TiO ₂ ), and zirconium oxide (ZrO ₂ ) or a combination thereof. The formation method of the high-k dielectric layer 108 is, for example, chemical vapor deposition.

Next, a dielectric layer 110 is formed on the substrate 100 . For example, dielectric layer 110 may be formed on high-k dielectric layer 108 . The dielectric layer 110 fills the trenches T1 and T2. The material of the dielectric layer 110 is, for example, silicon oxide formed by a high aspect ratio process (HARP). In addition, the dielectric layer 110 and the high-k dielectric layer 108 located in the trench T1 can serve as the deep trench isolation structure DT1, and the dielectric layer 110 and the high-k dielectric layer 108 located in the trench T2 can be used as the deep trench isolation structure DT1. as the deep trench isolation structure DT2. In some embodiments, the slit SS1 may exist in the deep trench isolation structure DT1, and the slit SS2 may exist in the deep trench isolation structure DT2.

Referring to FIG. 1C, a light shielding layer 112 may be formed on the dielectric layer 110 of the first region R1, and a light shielding layer 114 may be formed on the dielectric layer 110 of the second region R2. The light shielding layer 114 can block light to prevent optical crosstalk in the pixel region R2 and improve light sensitivity. The light shielding layer 114 may be located above the trench T2. For example, the light shielding layer 114 may be located directly above the trench T2. The material of the light shielding layer 112 and the light shielding layer 114 is, for example, a metal such as tungsten. The forming method of the light shielding layer 112 and the light shielding layer 114 is, for example, firstly forming a light shielding material layer (not shown) on the dielectric layer 110 by a deposition process, and then patterning the light shielding material layer by a lithography process and an etching process.

Referring to FIG. 1D , a capping layer 116 covering the light shielding layer 112 may be formed. In addition, the cap layer 116 can further cover the light shielding layer 114 . The material of the capping layer 116 is, for example, silicon oxide. The formation method of the cap layer 116 is, for example, a chemical vapor deposition method.

Next, an opening OP1 is formed in the cap layer 116 and the light shielding layer 112 . The opening OP1 is formed by patterning the cap layer 116 and the light shielding layer 112 by, for example, a lithography process and an etching process. In some embodiments, the above-mentioned patterning process can further remove a portion of the dielectric layer 110 so that the opening OP1 extends into the dielectric layer 110 .

Referring to FIG. 1E , a light-shielding material layer 118 is conformally formed on the surface of the opening OP1 . The material of the light-shielding material layer 118 is, for example, a metal such as tungsten. The formation method of the light shielding material layer 118 is, for example, a chemical vapor deposition method.

Referring to FIG. 1F , an etch-back process is performed on the light-shielding material layer 118 to expose the dielectric layer 110 and the cap layer 116 , and form a light-shielding wall 118 a. The etching back process is, for example, a dry etching process. Thereby, the light shielding structure LS1 can be formed above the photosensitive element 102 in the first region R1. There are openings OP2 between adjacent light shielding structures LS1. Thereby, in the subsequent hydrogen sintering process, the gas remaining in the deep trench isolation structure DT1 can be smoothly exhausted from the opening OP2. The opening OP2 may be located above the trench T1. For example, the opening OP2 may be located directly above the trench T1. The bottom of the opening OP2 may be higher than the top of the trench T1.

The light-shielding structure LS1 includes a light-shielding layer 112 and a light-shielding wall 118a. In the present embodiment, the light-shielding layer 112 and the light-shielding wall 118a may be independent components, that is, the light-shielding layer 112 and the light-shielding wall 118a may be formed by successively formed films instead of the same film. The light shielding layer 112 is disposed on the dielectric layer 110 . The light shielding layer 112 may be located above the photosensitive element 102 . For example, the light shielding layer 112 may be located directly above the photosensitive element 102 .

The light-shielding wall 118 a is connected to the light-shielding layer 112 and extends along the direction D1 toward the substrate 100 . Therefore, light can be blocked by the light shielding layer 112 and the light shielding wall 118 a to prevent the light from being irradiated to the photosensitive element 102 . For example, the light-shielding wall 118a may be connected to the sidewall of the light-shielding layer 112 . In some embodiments, the direction D1 toward the substrate 100 may be perpendicular to the top surface (eg, the second surface S2 ) of the substrate 100 . In this embodiment, the light-shielding wall 118a may have a portion higher than the light-shielding layer 112 and a portion lower than the light-shielding layer 112 at the same time, thereby further enhancing the light-shielding effect of the light-shielding structure LS1, but the present invention is not limited thereto . The opening OP2 is located between the light-shielding walls 118a of the adjacent light-shielding structures LS1. As shown in FIG. 2 , the top-view shape of the light-shielding wall 118a may be a rectangular ring. In addition, the width W1 of the opening OP2 may be smaller than the width W2 of the trench T1. For example, the width W1 of the opening OP2 may be 50% to 75% of the width W2 of the trench T1. In addition, the width W3 of the light-shielding wall 118a may be 25% to 50% of the width W2 of the trench T1.

Referring to FIG. 1G , a capping layer 120 may be formed on the capping layer 116 . The capping layer 120 may fill the opening OP2. The material of the capping layer 120 is, for example, silicon oxide. The formation method of the cap layer 120 is, for example, a chemical vapor deposition method. In some embodiments, after the capping layer 120 is formed, a planarization process, such as a chemical mechanical polishing process, may be performed on the capping layer 120 .

Hereinafter, the image sensor 10 of this embodiment will be described with reference to FIG. 1G . In addition, although the method for forming the image sensor 10 is described by taking the above method as an example, the present invention is not limited thereto.

Referring to FIG. 1G , the image sensor 10 includes a substrate 100 , a photosensitive element 102 , a photosensitive element 104 , a dielectric layer 110 , a light-shielding structure LS1 and a light-shielding structure LS2 . The image sensor 10 may be a backside illuminated image sensor (BSI image sensor). The substrate 100 includes the first region R1. The substrate 100 has a trench T1 in the first region R1. In some embodiments, the substrate 100 may be disposed on the carrier substrate 106 . The photosensitive element 102 is located in the substrate 100 of the first region R1. The trench T1 is located on the side of the photosensitive element 102 . The dielectric layer 110 is disposed on the substrate 100 and fills the trench T1. The light-shielding structure LS1 is located above the photosensitive element 102 . There are openings OP2 between adjacent light shielding structures LS1. The light-shielding structure LS1 includes a light-shielding layer 112 and a light-shielding wall 118a. The light shielding layer 112 is disposed on the dielectric layer 110 . The light-shielding wall 118 a is connected to the light-shielding layer 112 and extends along the direction D1 toward the substrate 100 . The opening OP2 is located between the light-shielding walls 118a of the adjacent light-shielding structures LS1. In addition, the opening OP2 may be located above the trench T1.

In addition, the substrate 100 may further include the second region R2. The substrate 100 may have a trench T2 in the second region R2. The dielectric layer 110 may fill the trench T2. The photosensitive element 104 is located in the substrate 100 in the second region R2. The trench T2 is located on the side of the photosensitive element 104 . The shading structure LS2 is located above the trench T2. In this embodiment, the light shielding structure LS2 may include a light shielding layer 114 . The light shielding layer 114 is disposed on the dielectric layer 110 . The image sensor 10 may further include a high-k dielectric layer 108 , and the high-k dielectric layer 108 is disposed between the dielectric layer 110 and the substrate 100 . The cap layer 116 is disposed on the light-shielding structure LS1 and the light-shielding structure LS2. The cap layer 120 is disposed on the cap layer 116 and fills the opening OP2.

In addition, the materials, setting methods, forming methods, dimensional relationships and functions of the components in the image sensor 10 have been described in detail in the above-mentioned embodiments, and will not be described herein again.

Based on the above embodiments, in the image sensor 10 and the manufacturing method thereof, since the light-shielding structures LS1 are located in the first region R1, and there is an opening OP2 between adjacent light-shielding structures LS1, in the subsequent hydrogen sintering process, The gas remaining in the deep trench isolation structure DT1 can be smoothly exhausted from the opening OP2 , thereby improving the electrical performance of the image sensor 10 . In addition, since the light-shielding wall 118a is connected to the light-shielding layer 112 and extends along the direction D1 toward the substrate 100, light can be blocked by the light-shielding layer 112 and the light-shielding wall 118a to prevent the light from being irradiated in the first region R1. Photosensitive element 102 . In some embodiments, the light-shielding wall 118 may have a portion higher than the light-shielding layer 112 and a portion lower than the light-shielding layer 112 at the same time, thereby further enhancing the light-shielding effect of the light-shielding structure LS1 .

3A to 3F are cross-sectional views illustrating a manufacturing process of an image sensor according to an embodiment of the present invention. FIG. 4 is a top view of the groove and the photosensitive element in FIG. 3C . FIG. 5 is a top view of the light-shielding structure and the photosensitive element in FIG. 3E .

Referring to FIG. 3A , a substrate 200 is provided. The substrate 200 may include the first region R3. The first region R3 may be a black level calibration (BLC) region. In addition, the substrate 200 may further include the second region R4. The second region R4 may be a pixel region. The substrate 200 may have a first surface S3 and a second surface S4 opposite to each other. The substrate 200 may be a semiconductor substrate, such as a silicon substrate such as an epitaxial silicon substrate, but the invention is not limited thereto.

Next, the photosensitive element 202 may be formed in the substrate 200 of the first region R3, and the photosensitive element 204 may be formed in the substrate 200 of the second region R4. The photosensitive element 202 and the photosensitive element 204 may be adjacent to the first surface S3 of the substrate 200 . The photosensitive element 202 and the photosensitive element 204 are, for example, photodiodes. The formation method of the photosensitive element 202 and the photosensitive element 204 is, for example, an ion implantation method.

In addition, required semiconductor elements (not shown) such as transistors, dielectric layers or interconnect structures can be formed on the first surface S3 of the substrate 200 , and the description thereof is omitted here.

In some embodiments, substrate 200 may be disposed on carrier substrate 206 . The carrier substrate 206 may be a semiconductor substrate, such as a silicon substrate, but the invention is not limited thereto.

Next, a trench T3 may be formed in the substrate 200 of the first region R3, and a trench T4 may be formed in the substrate 200 of the second region R4. The trench T3 is located on the side of the photosensitive element 202 . The trench T4 is located on the side of the photosensitive element 204 . The trenches T3 and T4 may be deep trenches. The trench T3 and the trench T4 are formed by, for example, patterning the second surface S4 of the substrate 200 through a lithography process and an etching process.

Referring to FIG. 3B , a high-k dielectric layer 208 may be formed on the substrate 200 . The high-k dielectric layer 208 can be used to limit the movement path of electrons to prevent electrons from being freed between adjacent photosensitive elements (eg, between adjacent photosensitive elements 202 or between adjacent photosensitive elements 204). interference caused by movement. The material of the high-k dielectric layer 208 is, for example, tantalum oxide, aluminum oxide, hafnium oxide (HfO ₂ ), titanium oxide, zirconium oxide, or a combination thereof. The formation method of the high-k dielectric layer 208 is, for example, chemical vapor deposition.

Next, a dielectric layer 210 is formed on the substrate 200 . For example, dielectric layer 210 may be formed on high-k dielectric layer 208 . The dielectric layer 210 fills the trenches T3 and T4. The material of the dielectric layer 210 is, for example, silicon oxide formed by a high aspect ratio trench filling process. In addition, the dielectric layer 210 and the high-k dielectric layer 208 located in the trench T3 can serve as the deep trench isolation structure DT3, and the dielectric layer 210 and the high-K dielectric layer 208 located in the trench T4 can be used as the deep trench isolation structure DT3. As the deep trench isolation structure DT4. In some embodiments, slits SS3 may exist in deep trench isolation structure DT3, and slits SS4 may exist in deep trench isolation structure DT4.

Referring to FIG. 3C, a groove RS1 may be formed in the dielectric layer 210 of the first region R3, and a groove RS2 may be formed in the dielectric layer 210 of the second region R4. The formation method of the groove RS1 and the groove RS2 is, for example, patterning the dielectric layer 210 through a lithography process and an etching process. The top-view shapes of the grooves RS1 and RS2 may be rectangular rings as shown in FIG. 4 .

Referring to FIG. 3D , a light-shielding material layer 212 filling the grooves RS1 and RS2 may be formed on the dielectric layer 210 . The material of the light-shielding material layer 212 is, for example, a metal such as tungsten. The formation method of the light shielding material layer 212 is, for example, a chemical vapor deposition method.

3E, the light-shielding material layer 212 may be patterned to form a light-shielding structure LS3 over the photosensitive element 202 in the first region R3, and a light-shielding structure LS4 over the trench T4 in the second region R4. For example, the light-shielding material layer 212 can be patterned through a lithography process and an etching process. In some embodiments, the above patterning process can further remove a portion of the dielectric layer 210 .

There are openings OP3 between adjacent light shielding structures LS3. Thereby, in the subsequent hydrogen sintering process, the gas remaining in the deep trench isolation structure DT3 can be smoothly exhausted from the opening OP3. The opening OP3 may be located above the trench T3. For example, the opening OP3 may be located directly above the trench T3. The bottom of the opening OP3 may be higher than the top of the trench T3.

The light-shielding structure LS3 includes a light-shielding layer 212a and a light-shielding wall 212b. In this embodiment, the light-shielding layer 212a and the light-shielding wall 212b can be integrally formed, that is, the light-shielding layer 212a and the light-shielding wall 212b can be formed by the same film layer. The light shielding layer 212 a is disposed on the dielectric layer 210 . The light shielding layer 212a may be located above the photosensitive element 202 . For example, the light shielding layer 212a may be located directly above the photosensitive element 202 .

The light-shielding wall 212b is connected to the light-shielding layer 212a and extends along the direction D2 toward the substrate 200 . Therefore, the light can be blocked by the light shielding layer 212a and the light shielding wall 212b, so as to prevent the light from being irradiated to the photosensitive element 202 . For example, the light-shielding wall 212b may be connected to the bottom of the light-shielding layer 212a. In some embodiments, the direction D2 toward the substrate 200 may be perpendicular to the top surface (eg, the second surface S4 ) of the substrate 200 . As shown in FIG. 3E and FIG. 5 , the openings OP3 are located between the light-shielding walls 212 b of the adjacent light-shielding structures LS3 , and each light-shielding structure LS3 can respectively cover the photosensitive elements 202 below. Since the shape of the light-shielding wall 212b can be determined by the shape of the groove RS1, the top-view shape of the light-shielding wall 212b and the top-view shape of the groove RS1 can be similar shapes, such as a rectangular ring. In addition, the width W4 of the opening OP3 may be smaller than the width W5 of the trench T3. For example, the width W4 of the opening OP3 may be 50% to 75% of the width W5 of the trench T3. In addition, the width W6 of the light-shielding wall 212b may be 25% to 50% of the width W5 of the trench T3.

The light-shielding structure LS4 may include a light-shielding layer 212c and a light-shielding wall 212d. In this embodiment, the light-shielding structure LS4 can block the light by the light-shielding wall 212d in addition to the light-shielding layer 212c, so that the optical crosstalk can be more effectively prevented from being generated in the pixel region R4, and The photosensitivity can be further improved. In this embodiment, the light-shielding layer 212c and the light-shielding wall 212d can be integrally formed, that is, the light-shielding layer 212c and the light-shielding wall 212d can be formed by the same film layer. The light shielding layer 212c is disposed on the dielectric layer 210 . The light shielding layer 212c may be located above the trench T4. For example, the light shielding layer 212c may be located directly above the trench T4.

The light-shielding wall 212d is connected to the light-shielding layer 212c and extends along the direction D2 toward the substrate 200 . For example, the light-shielding wall 212d may be connected to the bottom of the light-shielding layer 212c. Since the shape of the light-shielding wall 212d can be determined by the shape of the groove RS2, the top-view shape of the light-shielding wall 212d and the top-view shape of the groove RS2 can be similar shapes, such as a rectangular ring.

As shown in FIG. 5 , the light-shielding structure LS4 may be grid-shaped to expose the underlying photosensitive element 204 . In addition, the light shielding structure LS4 may have an opening OP4 penetrating the light shielding structure LS4. The opening OP4 may be located above the photosensitive element 204 . For example, the opening OP4 may be located directly above the photosensitive element 204 .

Referring to FIG. 3F, a capping layer 214 may be formed on the light shielding structure LS3 and the light shielding structure LS4. The capping layer 214 may fill the openings OP3 and OP4. The material of the capping layer 214 is, for example, silicon oxide. The formation method of the cap layer 214 is, for example, a chemical vapor deposition method. In some embodiments, after the capping layer 214 is formed, a planarization process, such as a chemical mechanical polishing process, may be performed on the capping layer 214 .

Hereinafter, the image sensor 20 of this embodiment will be described with reference to FIG. 3F . In addition, although the method for forming the image sensor 20 is described by taking the above method as an example, the present invention is not limited thereto.

Referring to FIG. 3F , the image sensor 20 includes a substrate 200 , a photosensitive element 202 , a photosensitive element 204 , a dielectric layer 210 , a light-shielding structure LS3 and a light-shielding structure LS4 . The image sensor 20 may be a backside illuminated image sensor. The substrate 200 includes the first region R3. The substrate 200 has a trench T3 in the first region R3. In some embodiments, the substrate 200 may be disposed on the carrier substrate 206 . The photosensitive element 202 is located in the substrate 200 of the first region R3. The trench T3 is located on the side of the photosensitive element 202 . The dielectric layer 210 is disposed on the substrate 200 and fills the trench T3. The light-shielding structure LS3 is located above the photosensitive element 202 . There are openings OP3 between adjacent light shielding structures LS3. The light-shielding structure LS3 includes a light-shielding layer 212a and a light-shielding wall 212b. The light shielding layer 212 a is disposed on the dielectric layer 210 . The light-shielding wall 212b is connected to the light-shielding layer 212a and extends along the direction D2 toward the substrate 200 . The openings OP3 are located between the light-shielding walls 212b of the adjacent light-shielding structures LS3. In addition, the opening OP3 may be located above the trench T3.

In addition, the substrate 200 may further include the second region R4. The substrate 200 may have a trench T4 in the second region R4. Dielectric layer 210 may fill trench T4. The photosensitive element 204 is located in the substrate 200 of the second region R4. The trench T4 is located on the side of the photosensitive element 204 . The shading structure LS4 is located above the trench T4. The light shielding structure LS4 may have an opening OP4 penetrating the light shielding structure LS4. The opening OP4 may be located above the photosensitive element 204 . In this embodiment, the light-shielding structure LS4 may include a light-shielding layer 212c and a light-shielding wall 212d. The light shielding layer 212c is disposed on the dielectric layer 210 . The light-shielding wall 212d is connected to the light-shielding layer 212c and extends along the direction D2 toward the substrate 200 . The image sensor 20 may further include a high-k dielectric layer 208 , and the high-k dielectric layer 208 is disposed between the dielectric layer 210 and the substrate 200 . The cap layer 214 is disposed on the light-shielding structure LS3 and the light-shielding structure LS4, and fills the opening OP3 and the opening OP4.

In addition, the materials, setting methods, forming methods, dimensional relationships and functions of the components in the image sensor 20 have been described in detail in the above-mentioned embodiments, and will not be described herein again.

Based on the above embodiments, in the image sensor 20 and the manufacturing method thereof, since the light-shielding structures LS3 are located in the first region R3, and there is an opening OP3 between adjacent light-shielding structures LS3, in the subsequent hydrogen sintering process, The gas remaining in the deep trench isolation structure DT3 can be smoothly exhausted from the opening OP3 , thereby improving the electrical performance of the image sensor 20 . In addition, since the light-shielding wall 212b is connected to the light-shielding layer 212a and extends along the direction D2 toward the substrate 200, the light-shielding layer 212a and the light-shielding wall 212b can block light to prevent the light from being irradiated in the first region R3. Photosensitive element 202 .

To sum up, in the image sensor and the manufacturing method thereof proposed in the above-mentioned embodiments, since there are openings between the adjacent light-shielding structures in the first area, it is helpful for exhausting in the first area , thereby improving the electrical performance of the image sensor. In addition, since the light-shielding structure in the first area includes a connected light-shielding layer and a light-shielding wall, and the light-shielding wall extends in the direction toward the substrate, the light-shielding structure in the first area can effectively block light to prevent the light from being irradiated in place in the first area. Photosensitive elements in a zone.

Although the present invention has been disclosed above by the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention shall be determined by the scope of the appended patent application.

10, 20: Image sensor 100, 200: base 102, 104, 202, 204: Photosensitive elements 106, 206: Carrier substrate 108, 208: High-K dielectric layers 110, 210: Dielectric layer 112, 114, 212a, 212c: Light shielding layer 116, 120, 214: Cap layer 118, 212: shading material layer 118a, 212b, 212d: Blackout Walls D1, D2: Direction DT1~DT4: Deep trench isolation structure LS1~LS4: Shading structure OP1~OP4: Opening R1, R3: first zone R2, R4: The second zone RS1, RS2: Groove S1, S3: first side S2, S4: Second side SS1~SS4: Slit T1~T4: Ditch W1~W6: Width

1A to 1G are cross-sectional views illustrating a manufacturing process of an image sensor according to an embodiment of the present invention. FIG. 2 is a top view of the light-shielding wall and the photosensitive element in FIG. 1F . 3A to 3F are cross-sectional views illustrating a manufacturing process of an image sensor according to an embodiment of the present invention. FIG. 4 is a top view of the groove and the photosensitive element in FIG. 3C . FIG. 5 is a top view of the light-shielding structure and the photosensitive element in FIG. 3E .

10: Image sensor

100: base

102,104: Photosensitive element

106: Carrier substrate

108: High dielectric constant dielectric layer

110: Dielectric layer

112,114: Shading layer

116,120: Cap layer

118a: Blackout Walls

D1: Direction

DT1, DT2: Deep trench isolation structure

LS1, LS2: Shading structure

OP2: Opening

R1: District 1

R2: Zone 2

S1: The first side

S2: Second side

SS1, SS2: Slit

T1, T2: Trench

W1~W3: Width

Claims (20)

An image sensor, comprising: a substrate including a first area, wherein the substrate has a first trench located in the first area, and the first area is a black level calibration area; a first photosensitive element , located in the substrate of the first area, wherein the first trench is located on the side of the first photosensitive element; a dielectric layer is disposed on the substrate and filled in the first a trench; and a first light-shielding structure located above the first photosensitive element, wherein the first light-shielding structure completely shields the first photosensitive element, and a first opening is formed between adjacent first light-shielding structures, and The first light-shielding structure includes: a first light-shielding layer disposed on the dielectric layer; and a first light-shielding wall connected to the first light-shielding layer and extending in a direction toward the substrate, wherein the The first openings are located between the first light-shielding walls adjacent to the first light-shielding structures. The image sensor of claim 1, wherein the first opening is located above the first trench. The image sensor of claim 1, wherein the width of the first opening is smaller than the width of the first trench. The image sensor of claim 1, wherein the width of the first opening is 50% to 75% of the width of the first trench. The image sensor of claim 1, wherein the width of the first light-shielding wall is 25% to 50% of the width of the first trench. The image sensor of claim 1, wherein the direction toward the substrate is perpendicular to a top surface of the substrate. The image sensor of claim 1, wherein the top-view shape of the first light-shielding wall includes a rectangular ring. The image sensor according to claim 1, wherein the first light shielding layer and the first light shielding wall are independent components. The image sensor according to claim 1, wherein the first light shielding layer and the first light shielding wall are integrally formed. The image sensor according to claim 1, wherein the first light shielding layer is located above the first photosensitive element. The image sensor of claim 1, wherein the substrate further comprises a second region, the substrate has a second trench in the second region, and the dielectric layer fills the second region a trench, and the image sensor further includes: a second photosensitive element located in the substrate in the second region, wherein the second trench is located on the side of the second photosensitive element; and a first Two light-shielding structures are located above the second trenches, wherein the second light-shielding structures include: a second light-shielding layer disposed on the dielectric layer. The image sensor of claim 11, wherein the second light-shielding structure further comprises: a second light-shielding wall connected to the second light-shielding layer and extending in a direction toward the substrate, wherein the The second light-shielding structure has a penetration through the second light-shielding structure and the second opening is located above the second photosensitive element. The image sensor of claim 1, further comprising: a high-k dielectric layer disposed between the dielectric layer and the substrate. A method of manufacturing an image sensor, comprising: providing a substrate, including a first area, wherein the first area is a black level calibration area; forming a first photosensitive element in the substrate in the first area; A first trench is formed in the substrate of the first region, wherein the first trench is located on the side of the first photosensitive element; a dielectric layer is formed on the substrate, wherein the dielectric layer is filled with into the first trench; and forming a first light-shielding structure above the first photosensitive element, wherein the first light-shielding structure completely shields the first photosensitive element, and there is a second light-shielding structure between adjacent first light-shielding structures. an opening, and the first light-shielding structure includes: a first light-shielding layer disposed on the dielectric layer; and a first light-shielding wall connected to the first light-shielding layer and along the direction toward the substrate extending, wherein the first opening is located above the first trench. The method for manufacturing an image sensor according to claim 14, wherein the method for forming the first light-shielding structure comprises: forming the first light-shielding layer on the dielectric layer in the first region; forming a cover a top cover layer of the first light shielding layer; a second opening is formed in the top cover layer and the first light shield layer; Conformally forming a light-shielding material layer on the surface of the second opening; and performing an etch-back process on the light-shielding material layer to expose the dielectric layer and the cap layer, and form the first Blackout wall. The manufacturing method of an image sensor according to claim 15, wherein the substrate further comprises a second region, and the manufacturing method of the image sensor further comprises: forming in the substrate of the second region a second photosensitive element; forming a second trench in the substrate in the second region, wherein the second trench is located on the side of the second photosensitive element; forming the dielectric layer on the substrate , wherein the dielectric layer fills the second trench; and a second light shielding layer is formed on the dielectric layer in the second region, and the second light shielding layer is located on the second trench above. The method for manufacturing an image sensor according to claim 14, wherein the method for forming the first light-shielding structure comprises: forming a first groove in the dielectric layer of the first region; forming a light-shielding material layer filling the first groove on the electrical layer; and patterning the light-shielding material layer to form the first light-shielding structure above the first photosensitive element. The method for manufacturing an image sensor according to claim 17, wherein the top-view shape of the first groove includes a rectangular ring. The method for manufacturing an image sensor according to claim 17, wherein the substrate further comprises a second region, and the method for manufacturing the image sensor further comprises: A second photosensitive element is formed in the substrate in the second area; a second trench is formed in the substrate in the second area, wherein the second trench is located on the side of the second photosensitive element ; forming the dielectric layer on the substrate, wherein the dielectric layer fills the second trench; forming a second groove in the dielectric layer in the second region; forming a second groove in the dielectric layer forming the light-shielding material layer filling the second groove on the electrical layer; and patterning the light-shielding material layer to form the second light-shielding structure above the second trench, wherein the first The two light-shielding structures include: a second light-shielding layer disposed on the dielectric layer; and a second light-shielding wall connected to the second light-shielding layer and extending in a direction toward the substrate. The method for manufacturing an image sensor according to claim 14, further comprising: forming a high-k dielectric layer on the substrate after forming the first trench and before forming the dielectric layer.

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