Image sensor, isolation structure, manufacturing method of isolation structure and graphical mask

Abstract

The invention discloses an image sensor, an isolation structure, a manufacturing method of the isolation structure and a patterned mask, and the manufacturing method of the isolation structure comprises the steps: forming a patterned photoresist layer on a substrate, and forming a plurality of parallel photoresist strips, a plurality of photoresist connection parts and a plurality of ion injection openings on the photoresist layer, the ion injection openings are parallel to the extending direction of the photoresist strips, and the photoresist connecting parts are located between every two adjacent ion injection openings and connect every two adjacent photoresist strips, so that all the photoresist strips are connected together through the photoresist connecting parts to form a whole, and the stability is better; the problem that the light resistor is easy to collapse and fall off when the isolation structure of the small-size image sensor is manufactured is avoided; and respectively manufacturing a first ion-doped isolation structure strip and a second ion-doped isolation structure strip through the photoresist layer so as to jointly form an isolation structure in the image sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of image sensors, and particularly to an image sensor, an isolation structure, a manufacturing method thereof, and a patterning mask. Background Art

[0002] CMOS image sensors (CIS) are widely used in digital still cameras, cellular phones, security cameras, and medical, automotive, and other applications. A typical image sensor operates in response to incident image light reflected from an external scene onto the image sensor. The image sensor includes a pixel array having photosensitive elements (e.g., photodiodes) that absorb a portion of the incident image light and generate image charges immediately after absorbing the image light. The image charge of each of the pixels can be measured as an output voltage of each photosensitive element that varies with the incident image light. In other words, the amount of image charge generated is proportional to the intensity of the image light, which is used to generate a digital image representing the external scene.

[0003] Figure 1 and Figure 2 As shown, in a CMOS image sensor, a plurality of pixels are arranged in an array. Each pixel has a photodiode PD, and the isolation structure 20 isolates the plurality of pixels from each other. The isolation structure 20 is formed by the intersection of a first ion-doped isolation structure strip 21 in the row direction and a second ion-doped isolation structure strip 22 in the column direction. As the requirements for the application of CMOS image sensors become higher and higher, the corresponding pixel size requirements become smaller and smaller, so that more pixel points can be obtained within the same area. In terms of pixel design, the distance between adjacent pixel points also decreases accordingly. The advantage of small pixels is that more pixel points can be obtained on the same area. To obtain higher pixels and a clearer image means obtaining the same full well capacity as large pixels on a smaller photosensitive area. To obtain the same full well capacity on a smaller area, it is often necessary to develop in the depth direction of the pixel. In terms of process, this means implanting the N-type ions forming the photodiode and the P-type ions of the isolation structure 20 isolating each pixel deeper.

[0004] Figures 3 to 5As shown in the figure, when manufacturing the isolation structure 20, it is necessary to coat a photoresist layer 30 on the substrate 10, pattern the photoresist layer 30 to form an ion implantation opening 301 corresponding to the pattern of the isolation structure 20, and then perform ion implantation with the patterned photoresist layer 30 as a mask to form the isolation structure 20. However, for the isolation structure 20 that requires high-dose ion implantation, a relatively thick photoresist layer 30 (e.g., >2um) is needed. After the photoresist layer 30 is patterned, a plurality of photoresist columns corresponding to pixels are formed. When manufacturing the isolation structure 20 of small pixels, the aspect ratio of each photoresist column is relatively large, which easily causes the photoresist columns to collapse and fall off, making it difficult to improve the yield of the device. Summary of the Invention

[0005] In order to overcome the disadvantages and deficiencies existing in the prior art, the purpose of the present invention is to provide an image sensor, an isolation structure, a manufacturing method thereof, and a patterning mask plate to solve the problem that the photoresist columns are prone to collapse and fall off when manufacturing the isolation structure of a small-size image sensor in the prior art.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] The present invention provides a manufacturing method for an isolation structure, including:

[0008] Providing a substrate; and manufacturing an isolation structure in the substrate;

[0009] Wherein, the manufacturing of the isolation structure includes at least one of the following steps:

[0010] Forming a first photoresist layer on the substrate and patterning the first photoresist layer, a plurality of mutually parallel first photoresist strips, a plurality of first photoresist connection parts, and a plurality of first ion implantation openings are formed on the first photoresist layer, the first ion implantation openings are parallel to the extension direction of the first photoresist strips, and the first photoresist connection parts are located between adjacent two of the first ion implantation openings and connect the adjacent two first photoresist strips; and

[0011] Forming a second photoresist layer on the substrate and patterning the second photoresist layer, a plurality of mutually parallel second photoresist strips, a plurality of second photoresist connection parts, and a plurality of second ion implantation openings are formed on the second photoresist layer, the second ion implantation openings are parallel to the extension direction of the second photoresist strips, and the second photoresist connection parts are located between adjacent two of the second ion implantation openings and connect the adjacent two second photoresist strips;

[0012] Wherein, the area of the first photoresist connection part corresponds to the area of the second ion implantation opening, and the area of the second photoresist connection part corresponds to the area of the first ion implantation opening;

[0013] The first ion implantation opening pattern corresponds to a first ion-doped isolation structure strip in the substrate, and the first ion-doped isolation structure strip has a first gap in a region corresponding to the first photoresist connection portion; the second ion implantation opening pattern corresponds to a second ion-doped isolation structure strip in the substrate, and the second ion-doped isolation structure strip has a second gap in a region corresponding to the second photoresist connection portion;

[0014] The isolation structure in the image sensor is formed based on the first ion-doped isolation structure strip and the second ion-doped isolation structure strip.

[0015] Optionally, the fabrication of the isolation structure specifically includes the following steps:

[0016] A first photoresist layer is formed on the substrate, and the first photoresist layer is patterned. Multiple mutually parallel first photoresist strips, multiple first photoresist connection portions, and multiple first ion implantation openings are formed on the first photoresist layer. The first ion implantation openings are parallel to the extending direction of the first photoresist strips. The first photoresist connection portions are located between two adjacent first ion implantation openings and connect the two adjacent first photoresist strips to each other;

[0017] Using the patterned first photoresist layer as a mask, the substrate is subjected to a first ion implantation to form a first ion-doped isolation structure strip corresponding to the first ion implantation opening pattern in the substrate, and the first photoresist layer is stripped. The first ion-doped isolation structure strip has the first gap in a region corresponding to the first photoresist connection portion;

[0018] A second photoresist layer is formed on the substrate, and the second photoresist layer is patterned. Multiple mutually parallel second photoresist strips, multiple second photoresist connection portions, and multiple second ion implantation openings are formed on the second photoresist layer. The second ion implantation openings are parallel to the extending direction of the second photoresist strips. The second photoresist connection portions are located between two adjacent second ion implantation openings and connect the two adjacent second photoresist strips to each other. The region of the first photoresist connection portion corresponds to the second ion implantation opening, and the region of the second photoresist connection portion corresponds to the first ion implantation opening;

[0019] Using the patterned second photoresist layer as a mask, the substrate is subjected to a second ion implantation to form a second ion-doped isolation structure strip corresponding to the second ion implantation opening pattern in the substrate, and the second photoresist layer is stripped. The second ion-doped isolation structure strip has the second gap in a region corresponding to the second photoresist connection portion;

[0020] The first ion-doped isolation structure strip and the second ion-doped isolation structure strip together form an isolation structure in an image sensor.

[0021] Optionally, the extending direction of the first ion implantation opening intersects with the extending direction of the second ion implantation opening.

[0022] Optionally, the included angle range between the extending direction of the first ion implantation opening and the extending direction of the second ion implantation opening is 30° to 90°.

[0023] Optionally, both the first photoresist connection portion and the second photoresist connection portion are rectangular or parallelogram-shaped.

[0024] Optionally, the first ion implantation opening extends along the row direction, and the second ion implantation opening extends along the column direction; or, the first ion implantation opening extends along the column direction, and the second ion implantation opening extends along the row direction.

[0025] Optionally, the area of each first ion implantation opening corresponds to at least one second photoresist connection portion, and the area of each second ion implantation opening corresponds to at least one first photoresist connection portion.

[0026] Optionally, the width of the first photoresist connection portion is greater than or equal to the width of the second ion implantation opening, and the width of the second photoresist connection portion is greater than or equal to the width of the first ion implantation opening.

[0027] Optionally, the first ion-doped isolation structure strip includes a first type of ion-doped isolation structure strip and a second type of ion-doped isolation structure strip. There is a first spacing between the first type of ion-doped isolation structure strip and the second ion-doped isolation structure strip, and there is a second spacing between the second type of ion-doped isolation structure strip and the second ion-doped isolation structure strip; and / or, the second ion-doped isolation structure strip includes a third type of ion-doped isolation structure strip and a fourth type of ion-doped isolation structure strip. There is a third spacing between the third type of ion-doped isolation structure strip and the first ion-doped isolation structure strip, and there is a fourth spacing between the fourth type of ion-doped isolation structure strip and the first ion-doped isolation structure strip.

[0028] Optionally, a third photoresist layer is used to replace the first photoresist layer and the second photoresist layer to form the first ion-doped isolation structure strip and the second ion-doped isolation structure strip. Wherein, the width of the first gap corresponding to the first ion-doped isolation strip is greater than the width of the second ion-doped isolation strip at the corresponding position and / or the width of the second gap corresponding to the second ion-doped isolation strip is greater than the width of the first ion-doped isolation strip at the corresponding position, so as to correspond to the third photoresist connection portion in the third photoresist layer.

[0029] Optionally, at least two pixels under the same lens form a pixel unit for phase focusing. At least one focusing pitch is configured between adjacent in-phase information acquisition pixels of the pixel unit. The focusing pitch is formed based on the first gap and the corresponding second ion-doped isolation structure strip, or the focusing pitch is formed based on the second gap and the corresponding first ion-doped isolation structure strip.

[0030] Optionally, the included angle between the first ion-doped isolation structure strip and the second ion-doped isolation structure strip is less than 90°. One first ion-doped isolation structure strip and two second ion-doped isolation structure strips correspond to the same lens, or one second ion-doped isolation structure strip and two first ion-doped isolation structure strips correspond to the same lens.

[0031] Optionally, at least four adjacent pixels form a pixel unit to obtain image information based on the pixel unit. The pixels in the pixel unit are arranged in a Bayer base array, and pixels with different areas are divided based on the first ion-doped isolation structure strip and the second ion-doped isolation structure strip with an included angle less than 90°.

[0032] The present application also provides a patterned mask plate, which is applicable to the manufacturing method of the isolation structure described in any one of the above solutions. The patterned mask plate includes a first sub-mask plate and a second sub-mask plate. A first pattern area is provided on the first sub-mask plate, and a second pattern area is provided on the second sub-mask plate, where:

[0033] The first pattern area corresponds to the patterned first photoresist layer, and the second pattern area corresponds to the patterned second photoresist layer.

[0034] The present application also provides an isolation structure of an image sensor, which is manufactured by using the manufacturing method of the isolation structure described above. The isolation structure includes a first ion-doped isolation structure strip and a second ion-doped isolation structure strip formed by different ion implantation processes step by step. The first ion-doped isolation structure strip has a first gap in the area corresponding to the second ion-doped isolation structure strip, and the second ion-doped isolation structure strip has a second gap in the area corresponding to the first ion-doped isolation structure strip.

[0035] Optionally, the extending direction of the first ion-doped isolation structure strip intersects with the extending direction of the second ion-doped isolation structure strip.

[0036] Optionally, the range of the included angle between the extending direction of the first ion-doped isolation structure strip and the extending direction of the second ion-doped isolation structure strip is 30° to 90°.

[0037] Optionally, both the first gap and the second gap are rectangular or parallelogram-shaped.

[0038] Optionally, the first ion-doped isolation structure strip extends along the row direction, and the second ion-doped isolation structure strip extends along the column direction; or, the first ion-doped isolation structure strip extends along the column direction, and the second ion-doped isolation structure strip extends along the row direction.

[0039] Optionally, the area of each first ion-doped isolation structure strip corresponds to at least one of the second gaps, and the area of each second ion-doped isolation structure strip corresponds to at least one of the first gaps.

[0040] Optionally, the width of the first gap is greater than or equal to the width of the second ion-doped isolation structure strip, and the width of the second gap is greater than or equal to the width of the first ion-doped isolation structure strip.

[0041] Optionally, at least two pixels under the same lens form a pixel unit for phase focusing. At least one focusing pitch is arranged between adjacent in-phase information acquisition pixels of the pixel unit. The focusing pitch is formed based on the first gap and the corresponding second ion-doped isolation structure strip, or the focusing pitch is formed based on the second gap and the corresponding first ion-doped isolation structure strip.

[0042] Optionally, the included angle between the first ion-doped isolation structure strip and the second ion-doped isolation structure strip is less than 90°. One first ion-doped isolation structure strip and two second ion-doped isolation structure strips correspond to the same lens, or one second ion-doped isolation structure strip and two first ion-doped isolation structure strips correspond to the same lens.

[0043] The present application also provides an image sensor, including the isolation structure described above.

[0044] The beneficial effects of the present invention are as follows: By forming a patterned photoresist layer on a substrate, a plurality of mutually parallel photoresist strips, a plurality of photoresist connection parts, and a plurality of ion implantation openings are formed on the photoresist layer. The ion implantation openings are parallel to the extending direction of the photoresist strips, and the photoresist connection parts are located between two adjacent ion implantation openings and connect two adjacent photoresist strips to each other. Thus, all the photoresist strips are connected together through the photoresist connection parts to form a whole, so as to have better stability and avoid the problems that the photoresist is prone to collapse and fall off when manufacturing the isolation structure of a small-size image sensor. Further, the first ion-doped isolation structure strips and the second ion-doped isolation structure strips in two different directions can be respectively manufactured through the photoresist layer to jointly form the isolation structure in the image sensor, ensuring that the isolation structure of the small-size image sensor can be manufactured on the premise that the photoresist will not collapse and fall off. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a schematic plan view of an image sensor in the prior art;

[0046] Figure 2 is a schematic cross-sectional view of an image sensor in the prior art;

[0047] Figures 3 - 5 is a schematic process flow structure view of manufacturing an isolation structure on an image sensor in the prior art;

[0048] Figure 6 is a schematic plan view of an image sensor in Embodiment 1 of the present invention;

[0049] Figures 7a - 7e is a schematic process flow structure view of manufacturing an isolation structure on the image sensor in Embodiment 1 of the invention;

[0050] Figure 8 is a schematic plan view of an image sensor in Embodiment 3 of the present invention;

[0051] Figure 9 is one of the schematic plan views of an image sensor in Embodiment 4 of the present invention;

[0052] Figure 10 is the other schematic plan view of an image sensor in Embodiment 4 of the present invention;

[0053] Figure 11 is a schematic plan view of an image sensor in Embodiment 5 of the present invention;

[0054] Figure 12 is a schematic plan view of a third photoresist layer in another embodiment of Embodiment 5 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0056] When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views showing the device structure will be enlarged locally out of proportion, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention here. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0057] For convenience of description, spatial relationship terms such as "beneath", "below", "lower than", "under", "above", "on" etc. may be used herein to describe the relationship of one element or feature shown in the drawings with other elements or features. It will be understood that these spatial relationship terms are intended to encompass other directions of the device in use or operation besides the directions depicted in the drawings. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there can also be one or more intervening layers.

[0058] In the context of the present application, the structure in which the first feature is "above" the second feature described may include an embodiment where the first and second features are formed in direct contact, and may also include an embodiment where additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0059] It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0060] [Embodiment 1]

[0061] Figure 6 is a schematic plan view of the image sensor in Embodiment 1 of the present invention. Figures 7a - 7e is a schematic process flow diagram of manufacturing the isolation structure of the image sensor in Embodiment 1 of the invention.

[0062] As Figure 6 shown, and referring to Figures 7a to 7e , a method for manufacturing an isolation structure provided in Embodiment 1 of the present invention includes:

[0063] Provide a substrate 10, where the substrate 10 is made of silicon. There are no excessive restrictions on the type, size, structure, etc. of the substrate 10, and specific selections can be made according to needs.

[0064] As Figure 7a shown, a first photoresist layer 31 is formed on the substrate 10. A first mask plate (not shown in the figure) is used to pattern the first photoresist layer 31 (such as exposure and development). The first mask plate has a pattern corresponding to the first ion-doped isolation structure strip 21. Multiple mutually parallel first photoresist strips 311, multiple first photoresist connection parts 312, and multiple first ion implantation openings 313 are formed on the first photoresist layer 31. The first ion implantation openings 313 are parallel to the extension direction of the first photoresist strips 311. The first photoresist connection parts 312 are located between two adjacent first ion implantation openings 313 and connect the two adjacent first photoresist strips 311 to each other. That is, the two first ion implantation openings 313 on the same straight line are spaced apart from each other by the first photoresist connection part 312. Thus, all the first photoresist strips 311 are connected together by the first photoresist connection parts 312 to form a whole, so as to have better stability and avoid the problems that the photoresist is prone to collapse and fall off when manufacturing the isolation structure of a small-size image sensor. Among them, the first photoresist layer 31 can be a photoresist layer, and a positive photoresist or a negative photoresist can be used. Only the patterns of the light-transmitting area and the light-shielding area on the first mask plate need to be correspondingly changed.

[0065] As Figure 7b shown, using the patterned first photoresist layer 31 as a shield, the substrate 10 is subjected to a first ion implantation, so as to form a first ion-doped isolation structure strip 21 corresponding to the pattern of the first ion implantation openings 313 in the substrate 10. The first ion-doped isolation structure strip 21 has a first gap 211 in the area corresponding to the first photoresist connection part 312. That is, the two first ion-doped isolation structure strips 21 on the same straight line are spaced apart from each other by the first gap 211. After the first ion implantation, then the first photoresist layer 31 on the substrate 10 is peeled off.

[0066] As Figure 7cAs shown, a second photoresist layer 32 is formed on the substrate 10. A second mask plate (not shown in the figure) is used to pattern the second photoresist layer 32 (such as exposure and development). The second mask plate has a pattern corresponding to the second ion-doped isolation structure bars 22. Multiple mutually parallel second photoresist bars 321, multiple second photoresist connection parts 322, and multiple second ion implantation openings 323 are formed on the second photoresist layer 32. The second ion implantation openings 323 are parallel to the extension direction of the second photoresist bars 321. The second photoresist connection parts 322 are located between two adjacent second ion implantation openings 323 and connect two adjacent second photoresist bars 321 to each other, that is, two second ion implantation openings 323 on the same straight line are spaced apart from each other by the second photoresist connection parts 322. Thus, all the second photoresist bars 321 are connected together by the second photoresist connection parts 322 to form a whole, so as to have better stability and avoid the problems that the photoresist is prone to collapse and fall off when manufacturing the isolation structure of a small-size image sensor. Among them, the second photoresist layer 32 can be a photoresist layer, and a positive photoresist or a negative photoresist can be used. Only the patterns of the light-transmitting area and the light-shielding area on the second mask plate need to be correspondingly changed.

[0067] As Figure 7d and Figure 7e shown, Figure 7d Only the pattern of the second ion-doped isolation structure bars 22 is drawn. Using the patterned second photoresist layer 32 as a shield, a second ion implantation is performed on the substrate 10, so as to form second ion-doped isolation structure bars 22 corresponding to the pattern of the second ion implantation openings 323 in the substrate 10. The second ion-doped isolation structure bars 22 have a second gap 221 in the area corresponding to the second photoresist connection parts 322, that is, two second ion-doped isolation structure bars 22 on the same straight line are spaced apart from each other by the second gap 221. After the second ion implantation, then the second photoresist layer 32 on the substrate 10 is peeled off.

[0068] It can be combined Figure 7a and Figure 7c to view. Among them, the first photoresist connection part 312 corresponds to the area of the second ion implantation openings 323, and the second photoresist connection part 322 corresponds to the area of the first ion implantation openings 313. Combining Figure 7b , Figure 7d and Figure 7eAs a result, after the first ion implantation and the second ion implantation, a first gap 211 is formed in the region of the first ion-doped isolation structure strip 21 corresponding to the second ion-doped isolation structure strip 22, and a second gap 221 is formed in the region of the second ion-doped isolation structure strip 22 corresponding to the first ion-doped isolation structure strip 21, so as to ensure that the first ion-doped isolation structure strip 21 and the second ion-doped isolation structure strip 22 jointly form the isolation structure 20 in the image sensor, and avoid the isolation structure 20 from repeatedly implanting ions into the substrate 10 in the first gap 211 and the second gap 221, which affects the uniformity of the doping of the isolation structure 20. Among them, the doping doses of the first ion-doped isolation structure strip 21 and the second ion-doped isolation structure strip 22 can be selected to be different. In this embodiment, they are selected to be the same. For example, they are both P doping with the same dose.

[0069] Further, the extending direction of the first ion implantation opening 313 intersects with the extending direction of the second ion implantation opening 323. As a result, after ion implantation, the extending direction of the first ion-doped isolation structure strip 21 formed in the substrate 10 intersects with the extending direction of the second ion-doped isolation structure strip 22, so that the first ion-doped isolation structure strip 21 and the second ion-doped isolation structure strip 22 can mutually define and form a plurality of pixels ( Figure 6 ).

[0070] The included angle range between the extending direction of the first ion implantation opening 313 and the extending direction of the second ion implantation opening 323 is 30° to 90°. That is, after ion implantation, the included angle range between the extending direction of the first ion-doped isolation structure strip 21 formed in the substrate 10 and the extending direction of the second ion-doped isolation structure strip 22 is 30° to 90°. In this embodiment, the included angle between the extending direction of the first ion implantation opening 313 and the extending direction of the second ion implantation opening 323 is 90°, that is, the extending direction of the first ion-doped isolation structure strip 21 formed in the substrate 10 is perpendicular to the extending direction of the second ion-doped isolation structure strip 22. Among them, the first ion implantation opening 313 extends along the row direction, and the second ion implantation opening 323 extends along the column direction, so that the first ion-doped isolation structure strip 21 extends along the row direction and the second ion-doped isolation structure strip 22 extends along the column direction. Of course, in other embodiments, the first ion implantation opening 313 can also extend along the column direction, and the second ion implantation opening 323 extends along the row direction, so that the first ion-doped isolation structure strip 21 extends along the column direction and the second ion-doped isolation structure strip 22 extends along the row direction.

[0071] Further, both the first photoresist connection portion 312 and the second photoresist connection portion 322 are rectangular or parallelogram-shaped, and further can be rhombus-shaped or square-shaped. In this embodiment, since the included angle between the extending direction of the first ion implantation opening 313 and the extending direction of the second ion implantation opening 323 is 90°, both the first photoresist connection portion 312 and the second photoresist connection portion 322 are rectangular. Optionally, the width of the first ion implantation opening 313 is equal to the width of the second ion implantation opening 323. Therefore, both the first photoresist connection portion 312 and the second photoresist connection portion 322 are square-shaped.

[0072] The area of each first ion implantation opening 313 corresponds to at least one second photoresist connection portion 322, and the area of each second ion implantation opening 323 corresponds to at least one first photoresist connection portion 312. In this embodiment, the area of each first ion implantation opening 313 corresponds to one second photoresist connection portion 322, and the area of each second ion implantation opening 323 corresponds to one first photoresist connection portion 312. Optionally, the second photoresist connection portion 322 corresponds to the midpoint area of one first ion implantation opening 313, and the first photoresist connection portion 312 corresponds to the midpoint area of one second ion implantation opening 323. Of course, in other embodiments, the area of each first ion implantation opening 313 can also correspond to two or three second photoresist connection portions 322, and the area of each second ion implantation opening 323 can also correspond to two or three first photoresist connection portions 312.

[0073] Further, the width of the first photoresist connection portion 312 is greater than or equal to the width of the second ion implantation opening 323, and the width of the second photoresist connection portion 322 is greater than or equal to the width of the first ion implantation opening 313. In this embodiment, the width of the first photoresist connection portion 312 is equal to the width of the second ion implantation opening 323, and the width of the second photoresist connection portion 322 is equal to the width of the first ion implantation opening 313, so that the width of the first gap 211 is equal to the width of the second ion-doped isolation structure strip 22, and the width of the second gap 221 is equal to the width of the first ion-doped isolation structure strip 21, to ensure that the first ion-doped isolation structure strip 21 and the second ion-doped isolation structure strip 22 can be seamlessly spliced together to form the isolation structure 20, and on the premise of avoiding repeated ion implantation in some areas of the isolation structure 20, to improve the isolation performance of the isolation structure 20.

[0074] In this embodiment, the image sensor has a lens 40, as Figure 6 shown, each lens 40 corresponds to one pixel, that is, the projection of each lens 40 on the substrate 10 corresponds to one pixel. Of course, in other embodiments, it can also be that each lens 40 corresponds to multiple pixels, such as two, four, etc.

[0075] As Figure 6As shown in the figure, this embodiment also provides an isolation structure for an image sensor, which is fabricated by using the fabrication method of the isolation structure described above.

[0076] The isolation structure 20 includes a first ion-doped isolation structure strip 21 and a second ion-doped isolation structure strip 22 which are formed step by step by using different ion implantation processes. Among them, the first ion-doped isolation structure strip 21 is formed by performing a first ion implantation using a first photoresist layer 31, and the second ion-doped isolation structure strip 22 is formed by performing a second ion implantation using a second photoresist layer 32.

[0077] The first ion-doped isolation structure strip 21 has a first gap 211 in the region corresponding to the second ion-doped isolation structure strip 22, and the second ion-doped isolation structure strip 22 has a second gap 221 in the region corresponding to the first ion-doped isolation structure strip 21. That is, two first ion-doped isolation structure strips 21 on the same straight line are spaced apart from each other through the first gap 211, and two second ion-doped isolation structure strips 22 on the same straight line are spaced apart from each other through the second gap 221. Thereby, it is ensured that the first ion-doped isolation structure strip 21 and the second ion-doped isolation structure strip 22 jointly form the isolation structure 20 in the image sensor, and it is avoided that the isolation structure 20 repeatedly performs ion implantation on the substrate 10 in the regions of the first gap 211 and the second gap 221, which affects the doping uniformity of the isolation structure 20.

[0078] Furthermore, the extending direction of the first ion-doped isolation structure strip 21 intersects with the extending direction of the second ion-doped isolation structure strip 22, so that the first ion-doped isolation structure strip 21 and the second ion-doped isolation structure strip 22 can mutually define and form a plurality of pixels. Among them, the range of the included angle between the extending direction of the first ion-doped isolation structure strip 21 and the extending direction of the second ion-doped isolation structure strip 22 is 30° to 90°. In this embodiment, the included angle between the extending direction of the first ion-doped isolation structure strip 21 and the extending direction of the second ion-doped isolation structure strip 22 is 90°, that is, the extending direction of the first ion-doped isolation structure strip 21 is perpendicular to the extending direction of the second ion-doped isolation structure strip 22.

[0079] The first ion-doped isolation structure strip 21 extends along the row direction, and the second ion-doped isolation structure strip 22 extends along the column direction. Of course, in other embodiments, the first ion-doped isolation structure strip 21 extends along the column direction, and the second ion-doped isolation structure strip 22 extends along the row direction.

[0080] Both the first gap 211 and the second gap 221 are rectangular or parallelogram-shaped, and further can be rhombus-shaped or square-shaped. In this embodiment, since the extending direction of the first ion-doped isolation structure strip 21 is perpendicular to the extending direction of the second ion-doped isolation structure strip 22, both the first gap 211 and the second gap 221 are rectangular. Optionally, the width of the first ion-doped isolation structure strip 21 is equal to the width of the second ion-doped isolation structure strip 22, so both the first gap 211 and the second gap 221 are square-shaped.

[0081] The area of each first ion-doped isolation structure strip 21 corresponds to at least one second gap 221, and the area of each second ion-doped isolation structure strip 22 corresponds to at least one first gap 211. In this embodiment, the area of each first ion-doped isolation structure strip 21 corresponds to one second gap 221, and the area of each second ion-doped isolation structure strip 22 corresponds to one first gap 211. Optionally, the second gap 221 corresponds to the midpoint area of a first ion-doped isolation structure strip 21, and the first gap 211 corresponds to the midpoint area of a second ion-doped isolation structure strip 22. Of course, in other embodiments, the area of each first ion-doped isolation structure strip 21 can also correspond to two or three second gaps 221, and the area of each second ion-doped isolation structure strip 22 can also correspond to two or three first gaps 211.

[0082] Furthermore, the width of the first gap 211 is greater than or equal to the width of the second ion-doped isolation structure strip 22, and the width of the second gap 221 is greater than or equal to the width of the first ion-doped isolation structure strip 21. In this embodiment, the width of the first gap 211 is equal to the width of the second ion-doped isolation structure strip 22, and the width of the second gap 221 is equal to the width of the first ion-doped isolation structure strip 21, so as to ensure that the first ion-doped isolation structure strip 21 and the second ion-doped isolation structure strip 22 can be seamlessly joined together to form the isolation structure 20, and on the premise of avoiding repeated ion implantation in some areas of the isolation structure 20, the isolation performance of the isolation structure 20 can be improved.

[0083] In this embodiment, the image sensor has lenses 40, and each lens 40 corresponds to one pixel, that is, the projection of each lens 40 on the substrate 10 corresponds to one pixel. Of course, in other embodiments, it can also be that each lens 40 corresponds to multiple pixels, such as two, four, etc.

[0084] [Embodiment 2]

[0085] The isolation structure and the manufacturing method of the isolation structure provided in Embodiment 2 of the present invention are basically the same as those of the isolation structure and the manufacturing method of the isolation structure in Embodiment 1 ( Figures 6 to 7e ), the difference is that in this embodiment:

[0086] The range of the included angle between the extending direction of the first ion implantation opening 313 and the extending direction of the second ion implantation opening 323 is 30° to 90°. In this embodiment, the included angle between the extending direction of the first ion implantation opening 313 and the extending direction of the second ion implantation opening 323 is an acute angle, such as 30°, 45°, 60°, etc., that is, the extending direction of the first ion implantation opening 313 and the extending direction of the second ion implantation opening 323 are not perpendicular. Therefore, both the first photoresist connection portion 312 and the second photoresist connection portion 322 are rhombuses. Of course, in other examples, both of them can also be non-rhombus parallelograms.

[0087] This embodiment also provides an isolation structure of an image sensor. The range of the included angle θ between the extending direction of the first ion-doped isolation structure strip 21 and the extending direction of the second ion-doped isolation structure strip 22 is 30° to 90°. In this embodiment, the included angle θ between the extending direction of the first ion-doped isolation structure strip 21 and the extending direction of the second ion-doped isolation structure strip 22 is an acute angle, such as 30°, 45°, 60°, etc., and the extending direction of the first ion-doped isolation structure strip 21 and the extending direction of the second ion-doped isolation structure strip 22 are not perpendicular. Therefore, both the first gap 211 and the second gap 221 are rhombuses. Of course, in other examples, both of them can also be non-rhombus parallelograms.

[0088] Those skilled in the art should understand that the rest of the structure and the working principle of this embodiment are the same as those of Embodiment 1, and will not be elaborated here.

[0089] [Embodiment 3]

[0090] Figure 8 is a schematic plan view of an image sensor in Embodiment 3 of the present invention. As Figure 8 shown, the isolation structure and the manufacturing method of the isolation structure provided in Embodiment 3 of the present invention are basically the same as those of the isolation structure and the manufacturing method of the isolation structure in Embodiment 1 ( Figures 6 to 7e ), Embodiment 2. The difference is that in this embodiment:

[0091] The first ion-doped isolation structure strip 21 includes a first type of ion-doped isolation structure strip 21a and a second type of ion-doped isolation structure strip 21b. The first type of ion-doped isolation structure strip 21a and the second type of ion-doped isolation structure strip 21b are parallel to each other and arranged alternately. For example, the first ion-doped isolation structure strip 21 corresponding to even rows is the first type of ion-doped isolation structure strip 21a, and the first ion-doped isolation structure strip 21 corresponding to odd rows is the second type of ion-doped isolation structure strip 21b. Among them, there is a first spacing d1 between the first type of ion-doped isolation structure strip 21a and the second ion-doped isolation structure strip 22, and there is a second spacing d2 between the second type of ion-doped isolation structure strip 21b and the second ion-doped isolation structure strip 22, that is, the width of the first gap 211 is greater than the width of the second ion-doped isolation structure strip 22.

[0092] In other embodiments, it may also be that there is a first spacing d1 between the first type of ion-doped isolation structure strip 21a and the second ion-doped isolation structure strip 22, while there is no spacing between the second type of ion-doped isolation structure strip 21b and the second ion-doped isolation structure strip 22, or rather, the second spacing d2 between the second type of ion-doped isolation structure strip 21b and the second ion-doped isolation structure strip 22 is 0, that is, the width of the first gap 211 between two adjacent first type of ion-doped isolation structure strips 21a on the same straight line is greater than the width of the second ion-doped isolation structure strip 22, and the width of the first gap 211 between two adjacent second type of ion-doped isolation structure strips 21b on the same straight line is equal to the width of the second ion-doped isolation structure strip 22. Or, it may also be that there is no spacing between the first type of ion-doped isolation structure strip 21a and the second ion-doped isolation structure strip 22, or rather, the first spacing d1 between the first type of ion-doped isolation structure strip 21a and the second ion-doped isolation structure strip 22 is 0, while there is a second spacing d2 between the second type of ion-doped isolation structure strip 21b and the second ion-doped isolation structure strip 22, that is, the width of the first gap 211 between two adjacent first type of ion-doped isolation structure strips 21a on the same straight line is equal to the width of the second ion-doped isolation structure strip 22, and the width of the first gap 211 between two adjacent second type of ion-doped isolation structure strips 21b on the same straight line is greater than the width of the second ion-doped isolation structure strip 22.

[0093] Furthermore, the widths of the first spacing d1 and the second spacing d2 are the same. Of course, in other embodiments, the widths of the first spacing d1 and the second spacing d2 may also be different. By configuring the spacing, it is beneficial to prevent the ion doping concentration in the cross-region of the isolation structure strips from being too high. An excessively high doping concentration leads to non-uniform doping. In addition, when the device is arranged in the isolation structure region, it is not conducive to the design of the device based on the required performance, thus affecting the process complexity and the performance defects of the pixel circuit, etc.

[0094] In this embodiment, the included angle between the extending direction of the first type of ion-doped isolation structure strip 21a and the extending direction of the second ion-doped isolation structure strip 22 is 90°. Of course, in other embodiments, the included angle between the extending direction of the first type of ion-doped isolation structure strip 21a and the extending direction of the second ion-doped isolation structure strip 22 can also be an acute angle, such as 30°, 45°, 60°, etc.; the included angle between the extending direction of the second type of ion-doped isolation structure strip 21b and the extending direction of the second ion-doped isolation structure strip 22 can also be an acute angle, such as 30°, 45°, 60°, etc.

[0095] In one embodiment, at least two pixels under the same lens 40 form a pixel unit for phase focusing. Among them, at least one focusing pitch is arranged between adjacent in-phase information acquisition pixels of the pixel unit. The focusing pitch is formed based on the first gap 211 and the corresponding second ion-doped isolation structure strip 22, or the focusing pitch is formed based on the second gap 221 and the corresponding first ion-doped isolation structure strip 21. Among them, the existence of the focusing pitch can be beneficial to the design of improving the focusing performance. For example, Figure 8 In the shown arrangement, when acquiring left and right phase information for focusing, a pitch can be arranged in the isolation structure between in-phase pixels, that is, there is no isolation structure at this pitch, thereby improving the focusing performance.

[0096] In this embodiment, the image sensor has lenses 40, and each lens 40 corresponds to four pixels, so as to realize phase focusing based on the four pixels, that is, the projection of each lens 40 on the substrate 10 corresponds to four pixels. Among them, each row of the first type of ion-doped isolation structure strips 21a penetrates through a row of lenses 40, and the second type of ion-doped isolation structure strips 21b correspond to the region between two rows of lenses 40. Further, the first type of ion-doped isolation structure strip 21a having a first pitch d1 penetrates through a row of lenses 40 and can be further arranged in the region at the center of the lens 40 with the first pitch d1. For example, Figure 8 In the two first pitches d1 are distributed on both sides of the center of the lens 40, and the second ion-doped isolation structure strip 22 passes through the center of the corresponding lens 40. It should be noted that the number of pixels under one lens 40 can be selected according to actual needs to realize phase focusing based on the pixels under one lens. In this embodiment, a pitch having at least one of the first pitch d1 and the second pitch d2 can be arranged in the pixel unit for realizing phase focusing.

[0097] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1 and Embodiment 2, and will not be elaborated here.

[0098] [Embodiment 4]

[0099] Figure 9 is one of the schematic plan views of the image sensor in Embodiment 4 of the present invention. Figure 10 is the second schematic plan view of the image sensor in Embodiment 4 of the present invention. As Figures 9 - 10 shown, the isolation structure and the manufacturing method of the isolation structure provided in Embodiment 4 of the present invention are basically the same as those of the isolation structure and the manufacturing method of the isolation structure in Embodiment 1 ( Figures 6 to 7e ), Embodiment 2. The difference lies in that in this embodiment:

[0100] The second ion-doped isolation structure strip 22 includes a third type of ion-doped isolation structure strip 22a and a fourth type of ion-doped isolation structure strip 22b, and the third type of ion-doped isolation structure strip 22a and the fourth type of ion-doped isolation structure strip 22b are arranged in parallel and alternately. For example, the second ion-doped isolation structure strip 22 corresponding to the even columns is the third type of ion-doped isolation structure strip 22a, and the second ion-doped isolation structure strip 22 corresponding to the odd columns is the fourth type of ion-doped isolation structure strip 22b.

[0101] As Figure 9 shown, there is a third spacing d3 between the third type of ion-doped isolation structure strip 22a and the first ion-doped isolation structure strip 21, while there is no spacing between the fourth type of ion-doped isolation structure strip 22b and the first ion-doped isolation structure strip 21, that is, the width of the second gap 221 between two adjacent third type of ion-doped isolation structure strips 22a on the same straight line is greater than the width of the first ion-doped isolation structure strip 21, and the width of the second gap 221 between two adjacent fourth type of ion-doped isolation structure strips 22b on the same straight line is equal to the width of the first ion-doped isolation structure strip 21. As Figure 10As shown, there is a third spacing d3 between the third type of ion-doped isolation structure strip 22a and the first ion-doped isolation structure strip 21, and a fourth spacing d4 between the fourth type of ion-doped isolation structure strip 22b and the first ion-doped isolation structure strip 21, that is, the width of the second gap 221 is greater than the width of the first ion-doped isolation structure strip 21. Or, in other embodiments, it may also be that there is no spacing between the third type of ion-doped isolation structure strip 22a and the first ion-doped isolation structure strip 21, while there is a fourth spacing d4 between the fourth type of ion-doped isolation structure strip 22b and the first ion-doped isolation structure strip 21, that is, the width of the second gap 221 between two adjacent third type of ion-doped isolation structure strips 22a on the same straight line is equal to the width of the first ion-doped isolation structure strip 21, and the width of the second gap 221 between two adjacent fourth type of ion-doped isolation structure strips 22b on the same straight line is greater than the width of the first ion-doped isolation structure strip 21.

[0102] Furthermore, as Figure 10 shown, the widths of the third spacing d3 and the fourth spacing d4 are the same. Of course, in other embodiments, the widths of the third spacing d3 and the fourth spacing d4 may also be different.

[0103] In an embodiment, the included angle between the first ion-doped isolation structure strip 21 and the second ion-doped isolation structure strip 22 is less than 90°. One lens 40 corresponds to one first ion-doped isolation structure strip 21 and two second ion-doped isolation structure strips 22, or one lens 40 corresponds to one second ion-doped isolation structure strip 22 and two first ion-doped isolation structure strips 21.

[0104] In another embodiment, there is a third spacing d3 between the third type of ion-doped isolation structure strip 22a and the first ion-doped isolation structure strip 21, while there is no spacing between the fourth type of ion-doped isolation structure strip 22b and the first ion-doped isolation structure strip 21, that is, the width of the second gap 221 between two adjacent third type of ion-doped isolation structure strips 22a on the same straight line is greater than the width of the first ion-doped isolation structure strip 21, and the width of the second gap 221 between two adjacent fourth type of ion-doped isolation structure strips 22b on the same straight line is equal to the width of the first ion-doped isolation structure strip 21. Among them, the extending direction of the third type of ion-doped isolation structure strip 22a and the extending direction of the first ion-doped isolation structure strip 21 are acute angles, such as 30°, 45°, 60°, etc.; and the extending direction of the fourth type of ion-doped isolation structure strip 22b is perpendicular to the extending direction of the first ion-doped isolation structure strip 21.

[0105] In this embodiment, the image sensor has lenses 40, and each lens 40 corresponds to four pixels, so as to achieve phase focusing based on the four pixels, that is, the projection of each lens 40 on the substrate 10 corresponds to four pixels. Among them, each column of the third type of ion-doped isolation structure strip 22a penetrates through a column of lenses 40, and the fourth type of ion-doped isolation structure strip 22b corresponds to the position between two columns of lenses 40.

[0106] Furthermore, the third type of ion-doped isolation structure strip 22a with a third pitch d3 penetrates through a column of lenses 40, and the third pitch d3 can be further arranged in the area at the center of the lens 40. For example, in the figure, two third pitches d3 are distributed on both sides of the center of the lens 40, and the first ion-doped isolation structure strip 21 passes through the center of the corresponding lens 40. It should be noted that the number of pixels under one lens 40 can be selected according to actual needs to achieve phase focusing based on the pixels under one lens 40. In this embodiment, at least one of the third pitch d3 and the fourth pitch d4 can be arranged in the pixel unit for achieving phase focusing.

[0107] In another implementation manner, it is also possible to divide the photosensitive area of the pixels based on the obliquely arranged isolation structure strip, so as to further improve the photosensitive performance of the entire image sensor. For example, one lens 40 can be replaced by four small lenses corresponding to the four pixels below one by one. Further, the four pixels are configured in an RGGB Bayer array arrangement, where two G pixels sensitive to the human eye have a larger photosensitive area, thereby improving the overall image quality. It should be noted that the pixels in the pixel unit can be arranged in a Bayer-based array, and can be other variants of the RGGB Bayer array arrangement, such as an RYYB or an RGBIR arrangement, etc.

[0108] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1 and Embodiment 2, and will not be elaborated here.

[0109] [Embodiment 5]

[0110] Figure 11 is a schematic plan view of the image sensor in Embodiment 5 of the present invention. As Figure 11 shown, the isolation structure and the manufacturing method of the isolation structure provided in Embodiment 5 of the present invention are basically the same as those of the isolation structure and the manufacturing method of the isolation structure in Embodiment 1 ( Figures 6 to 7e ), Embodiment 2. The difference is that in this embodiment:

[0111] The first ion-doped isolation structure strip 21 includes a first type of ion-doped isolation structure strip 21a and a second type of ion-doped isolation structure strip 21b, and the first type of ion-doped isolation structure strip 21a and the second type of ion-doped isolation structure strip 21b are parallel to each other and arranged alternately. For example, the first ion-doped isolation structure strip 21 corresponding to even rows is the first type of ion-doped isolation structure strip 21a, and the first ion-doped isolation structure strip 21 corresponding to odd rows is the second type of ion-doped isolation structure strip 21b. Among them, there is a first spacing d1 between the first type of ion-doped isolation structure strip 21a and the second ion-doped isolation structure strip 22, and there is a second spacing d2 between the second type of ion-doped isolation structure strip 21b and the second ion-doped isolation structure strip 22, that is, the width of the first gap 211 is greater than the width of the second ion-doped isolation structure strip 22. In other embodiments, it may also be that there is a first spacing d1 between the first type of ion-doped isolation structure strip 21a and the second ion-doped isolation structure strip 22, while there is no spacing between the second type of ion-doped isolation structure strip 21b and the second ion-doped isolation structure strip 22, that is, the width of the first gap 211 between two adjacent first type of ion-doped isolation structure strips 21a on the same straight line is greater than the width of the second ion-doped isolation structure strip 22, and the width of the first gap 211 between two adjacent second type of ion-doped isolation structure strips 21b on the same straight line is equal to the width of the second ion-doped isolation structure strip 22. Or, it may also be that there is no spacing between the first type of ion-doped isolation structure strip 21a and the second ion-doped isolation structure strip 22, while there is a second spacing d2 between the second type of ion-doped isolation structure strip 21b and the second ion-doped isolation structure strip 22, that is, the width of the first gap 211 between two adjacent first type of ion-doped isolation structure strips 21a on the same straight line is equal to the width of the second ion-doped isolation structure strip 22, and the width of the first gap 211 between two adjacent second type of ion-doped isolation structure strips 21b on the same straight line is greater than the width of the second ion-doped isolation structure strip 22.

[0112] The second ion-doped isolation structure strip 22 includes a third type of ion-doped isolation structure strip 22a and a fourth type of ion-doped isolation structure strip 22b. The third type of ion-doped isolation structure strip 22a and the fourth type of ion-doped isolation structure strip 22b are arranged side by side and alternately. For example, the second ion-doped isolation structure strip 22 corresponding to the even columns is the third type of ion-doped isolation structure strip 22a, and the second ion-doped isolation structure strip 22 corresponding to the odd columns is the fourth type of ion-doped isolation structure strip 22b. There is a third spacing d3 between the third type of ion-doped isolation structure strip 22a and the first ion-doped isolation structure strip 21, and there is a fourth spacing d4 between the fourth type of ion-doped isolation structure strip 22b and the first ion-doped isolation structure strip 21, that is, the width of the second gap 221 is greater than the width of the first ion-doped isolation structure strip 21. In other embodiments, it may also be that there is a third spacing d3 between the third type of ion-doped isolation structure strip 22a and the first ion-doped isolation structure strip 21, while there is no spacing between the fourth type of ion-doped isolation structure strip 22b and the first ion-doped isolation structure strip 21, that is, the width of the second gap 221 between two adjacent third type of ion-doped isolation structure strips 22a on the same straight line is greater than the width of the first ion-doped isolation structure strip 21, and the width of the second gap 221 between two adjacent fourth type of ion-doped isolation structure strips 22b on the same straight line is equal to the width of the first ion-doped isolation structure strip 21. Or, it may also be that there is no spacing between the third type of ion-doped isolation structure strip 22a and the first ion-doped isolation structure strip 21, while there is a fourth spacing d4 between the fourth type of ion-doped isolation structure strip 22b and the first ion-doped isolation structure strip 21, that is, the width of the second gap 221 between two adjacent third type of ion-doped isolation structure strips 22a on the same straight line is equal to the width of the first ion-doped isolation structure strip 21, and the width of the second gap 221 between two adjacent fourth type of ion-doped isolation structure strips 22b on the same straight line is greater than the width of the first ion-doped isolation structure strip 21.

[0113] Furthermore, the widths of the first spacing d1 and the second spacing d2 are the same. Of course, the widths of the first spacing d1 and the second spacing d2 may also be different. The widths of the third spacing d3 and the fourth spacing d4 are the same. Of course, the widths of the third spacing d3 and the fourth spacing d4 may also be different.

[0114] In this embodiment, the included angle between the extending direction of the first type of ion-doped isolation structure strip 21a and the extending direction of the second ion-doped isolation structure strip 22 is 90°. Of course, in other embodiments, the included angle between the extending direction of the first type of ion-doped isolation structure strip 21a and the extending direction of the second ion-doped isolation structure strip 22 can also be an acute angle, such as 30°, 45°, 60°, etc.; the included angle between the extending direction of the second type of ion-doped isolation structure strip 21b and the extending direction of the second ion-doped isolation structure strip 22 can also be an acute angle, such as 30°, 45°, 60°, etc.

[0115] In this embodiment, the included angle between the extending direction of the third type of ion-doped isolation structure strip 22a and the extending direction of the first ion-doped isolation structure strip 21 is 90°. Of course, in other embodiments, the included angle between the extending direction of the third type of ion-doped isolation structure strip 22a and the extending direction of the first ion-doped isolation structure strip 21 can also be an acute angle, such as 30°, 45°, 60°, etc.; the included angle between the extending direction of the fourth type of ion-doped isolation structure strip 22b and the extending direction of the first ion-doped isolation structure strip 21 can also be an acute angle, such as 30°, 45°, 60°, etc.

[0116] In this embodiment, the image sensor has lenses 40, and each lens 40 corresponds to four pixels, so as to achieve phase focusing based on the four pixels, that is, the projection of each lens 40 on the substrate 10 corresponds to four pixels. Among them, each row of the first type of ion-doped isolation structure strips 21a penetrates through a row of lenses 40, and the second type of ion-doped isolation structure strips 21b are corresponding to the space between two rows of lenses 40; each column of the third type of ion-doped isolation structure strips 22a penetrates through a column of lenses 40, and the fourth type of ion-doped isolation structure strips 22b are corresponding to the space between two columns of lenses 40.

[0117] Figure 12 It is a schematic plan view of the third photoresist layer in another embodiment of Embodiment 5 of the present invention. As Figure 12As shown, in another embodiment, a third photoresist layer 33 is used to replace the first photoresist layer 31 and the second photoresist layer 32 to form the first ion-doped isolation structure strip 21 and the second ion-doped isolation structure strip 22. The third photoresist layer 33 has a third ion implantation opening 331 and a third photoresist connection part 332. The third ion implantation opening 331 replaces the first ion implantation opening 313 and the second ion implantation opening 323, and the third photoresist connection part 332 replaces the first photoresist connection part 312 and the second photoresist connection part 322. Among them, the width of the first gap 211 corresponding to the first ion-doped isolation strip 21 is greater than the width of the second ion-doped isolation strip 22 at the corresponding position and / or the width of the second gap 221 corresponding to the second ion-doped isolation strip 22 is greater than the width of the first ion-doped isolation strip 21 at the corresponding position, so as to correspond to the third photoresist connection part 332 in the third photoresist layer 33. Refer to Figure 11 the corresponding isolation structure 20 obtained in. In this embodiment, based on the design method of the photoresist connection part, the collapse of the photoresist can be alleviated, which is beneficial to saving the process cost.

[0118] Those skilled in the art should understand that the rest of the structure and working principle of this embodiment are the same as those of the first embodiment and the second embodiment, and will not be elaborated here.

[0119] The present application also provides an image sensor, including the isolation structure 20 as described above. Among them, the first ion-doped isolation structure strip 21 and the second ion-doped isolation structure strip 22 of the isolation structure 20 define each other to form a plurality of pixels, and the isolation structure 20 separates the plurality of pixels from each other.

[0120] A lens 40 is further provided on the image sensor. Among them, each lens 40 corresponds to four pixels, so as to achieve phase focusing based on the four pixels, that is, the projection of each lens 40 on the substrate 10 corresponds to four pixels. Of course, in other embodiments, each lens 40 corresponds to sixteen pixels, and phase focusing is achieved based on the sixteen pixels, that is, the projection of each lens 40 on the substrate 10 corresponds to sixteen pixels.

[0121] The present application also provides a patterning mask, which is applicable to the manufacturing method of the isolation structure described in any one of the above solutions. Among them, the patterning mask includes a first sub-mask and a second sub-mask. Further, a first pattern area is provided on the first sub-mask, and a second pattern area is provided on the second sub-mask. Among them: the first pattern area corresponds to the patterned first photoresist layer, that is, the first photoresist layer is patterned based on the first sub-mask; the second pattern area corresponds to the patterned second photoresist layer, that is, the second photoresist layer is patterned based on the second sub-mask; thus, the isolation structure 20 of the image sensor is formed.

[0122] In this text, the orientation terms such as "upper", "lower", "left", "right", "front", and "back" are defined based on the positions of the structures in the accompanying drawings and their relative positions to each other, solely for the clarity and convenience of expressing the technical solution. It should be understood that the use of these orientation terms should not limit the scope of protection claimed in this application. It should also be understood that the terms "first" and "second" used herein are only for distinguishing names and do not limit the quantity and order.

[0123] The above are only the preferred embodiments of the present invention and do not impose any formal limitations on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, may make some changes or modifications using the above-disclosed technical content, which are equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A manufacturing method of an isolation structure, characterized in that The manufacturing method includes: providing a substrate; and fabricating an isolation structure in the substrate; wherein the fabrication of the isolation structure includes the following steps: forming a first photoresist layer on the substrate and performing a patterning process on the first photoresist layer, multiple mutually parallel first photoresist strips, multiple first photoresist connection parts, and multiple first ion implantation openings are formed on the first photoresist layer, the first ion implantation openings are parallel to the extending direction of the first photoresist strips, the first photoresist connection parts are located between two adjacent first ion implantation openings and connect the two adjacent first photoresist strips to each other; and forming a second photoresist layer on the substrate and performing a patterning process on the second photoresist layer, multiple mutually parallel second photoresist strips, multiple second photoresist connection parts, and multiple second ion implantation openings are formed on the second photoresist layer, the second ion implantation openings are parallel to the extending direction of the second photoresist strips, the second photoresist connection parts are located between two adjacent second ion implantation openings and connect the two adjacent second photoresist strips to each other; wherein the area of the first photoresist connection part corresponds to the area of the second ion implantation opening, and the area of the second photoresist connection part corresponds to the area of the first ion implantation opening; the first ion implantation opening pattern corresponds to a first ion-doped isolation structure strip in the substrate, and the first ion-doped isolation structure strip has a first gap in the area corresponding to the first photoresist connection part; the second ion implantation opening pattern corresponds to a second ion-doped isolation structure strip in the substrate, and the second ion-doped isolation structure strip has a second gap in the area corresponding to the second photoresist connection part; forming the isolation structure in the image sensor based on the first ion-doped isolation structure strip and the second ion-doped isolation structure strip.

2. The manufacturing method of the isolation structure according to claim 1, characterized in that The fabrication of the isolation structure specifically includes the following steps: forming the first photoresist layer on the substrate and performing a patterning process on the first photoresist layer, multiple mutually parallel first photoresist strips, multiple first photoresist connection parts, and multiple first ion implantation openings are formed on the first photoresist layer, the first ion implantation openings are parallel to the extending direction of the first photoresist strips, the first photoresist connection parts are located between two adjacent first ion implantation openings and connect the two adjacent first photoresist strips to each other; performing a first ion implantation on the substrate with the patterned first photoresist layer as a mask, forming the first ion-doped isolation structure strip corresponding to the first ion implantation opening pattern in the substrate, and stripping the first photoresist layer, and the first ion-doped isolation structure strip has the first gap in the area corresponding to the first photoresist connection part; A second photoresist layer is formed on the substrate, and the second photoresist layer is patterned. A plurality of mutually parallel second photoresist strips, a plurality of second photoresist connection parts, and a plurality of second ion implantation openings are formed on the second photoresist layer. The second ion implantation openings are parallel to the extension direction of the second photoresist strips. The second photoresist connection parts are located between two adjacent second ion implantation openings and connect the two adjacent second photoresist strips to each other. The first photoresist connection part corresponds to the area of the second ion implantation opening, and the second photoresist connection part corresponds to the area of the first ion implantation opening; Using the patterned second photoresist layer as a mask, the substrate is subjected to a second ion implantation to form the second ion-doped isolation structure strips corresponding to the pattern of the second ion implantation openings in the substrate, and then the second photoresist layer is stripped. The second ion-doped isolation structure strips have the second gap in the area corresponding to the second photoresist connection parts; The first ion-doped isolation structure strips and the second ion-doped isolation structure strips together form the isolation structure in the image sensor.

3. The manufacturing method of the isolation structure according to claim 1, wherein The extension direction of the first ion implantation openings intersects with the extension direction of the second ion implantation openings; Alternatively, the arrangement of the first ion implantation openings and the second ion implantation openings is such that the first ion implantation openings extend along the row direction and the second ion implantation openings extend along the column direction, or the first ion implantation openings extend along the column direction and the second ion implantation openings extend along the row direction.

4. The manufacturing method of the isolation structure according to claim 3, characterized in that, The range of the angle between the extension direction of the first ion implantation openings and the extension direction of the second ion implantation openings is 30° to 90°; or, at least four adjacent pixels form a pixel unit to obtain image information based on the pixel unit. The pixels in the pixel unit are arranged in a Bayer base array, and different area pixels are divided based on the first ion-doped isolation structure strips and the second ion-doped isolation structure strips with an angle less than 90°; 5. The manufacturing method of the isolation structure according to claim 1, characterized in that, Both the first photoresist connection part and the second photoresist connection part are rectangular or parallelogram-shaped; and / or, at least one second photoresist connection part corresponds to the area of each first ion implantation opening, and at least one first photoresist connection part corresponds to the area of each second ion implantation opening.

6. The method for manufacturing the isolation structure according to claim 1, characterized in that, The width of the first photoresist connection part is greater than or equal to the width of the second ion implantation opening, and the width of the second photoresist connection part is greater than or equal to the width of the first ion implantation opening.

7. The manufacturing method of the isolation structure according to claim 6, wherein The first ion-doped isolation structure strips include the first type of ion-doped isolation structure strips and the second type of ion-doped isolation structure strips. There is a first spacing between the first type of ion-doped isolation structure strips and the second ion-doped isolation structure strips, and there is a second spacing between the second type of ion-doped isolation structure strips and the second ion-doped isolation structure strips; And / or, the second ion-doped isolation structure strip includes a third type of ion-doped isolation structure strip and a fourth type of ion-doped isolation structure strip. There is a third spacing between the third type of ion-doped isolation structure strip and the first ion-doped isolation structure strip, and a fourth spacing between the fourth type of ion-doped isolation structure strip and the first ion-doped isolation structure strip.

8. The manufacturing method of the isolation structure according to claim 1, characterized in that, The first ion-doped isolation structure strip and the second ion-doped isolation structure strip are formed by using a third photoresist layer to replace the first photoresist layer and the second photoresist layer. Wherein, the width of the first gap corresponding to the first ion-doped isolation strip is greater than the width of the second ion-doped isolation strip at the corresponding position and / or the width of the second gap corresponding to the second ion-doped isolation strip is greater than the width of the first ion-doped isolation strip at the corresponding position, so as to correspond to the third photoresist connection part in the third photoresist layer.

9. The manufacturing method of the isolation structure according to any one of claims 1-8, characterized in that At least two pixels under the same lens form a pixel unit for phase focusing. Wherein, at least one focusing spacing is arranged between adjacent in-phase information acquisition pixels of the pixel unit, and the focusing spacing is formed based on the first gap and the corresponding second ion-doped isolation structure strip, or the focusing spacing is formed based on the second gap and the corresponding first ion-doped isolation structure strip.

10. The manufacturing method of the isolation structure according to claim 9, characterized in that, The included angle between the first ion-doped isolation structure strip and the second ion-doped isolation structure strip is less than 90°. The same lens corresponds to one first ion-doped isolation structure strip and two second ion-doped isolation structure strips, or the same lens corresponds to one second ion-doped isolation structure strip and two first ion-doped isolation structure strips.

11. A graphical mask, applicable to the manufacturing method of the isolation structure as described in any one of claims 1-10, characterized in that, The patterned mask plate includes a first sub-mask plate and a second sub-mask plate. A first pattern area is provided on the first sub-mask plate, and a second pattern area is provided on the second sub-mask plate, wherein: The first pattern area corresponds to the patterned first photoresist layer, and the second pattern area corresponds to the patterned second photoresist layer.

12. An isolation structure of an image sensor, characterized in that, It is made by using the manufacturing method of the isolation structure according to any one of claims 1-10. The isolation structure includes a first ion-doped isolation structure strip and a second ion-doped isolation structure strip which are made by different ion implantation processes step by step. The first ion-doped isolation structure strip has a first gap in the area corresponding to the second ion-doped isolation structure strip, and the second ion-doped isolation structure strip has a second gap in the area corresponding to the first ion-doped isolation structure strip.

13. The isolation structure of the image sensor according to claim 12, wherein The extending direction of the first ion-doped isolation structure strip intersects with the extending direction of the second ion-doped isolation structure strip; or, the first ion-doped isolation structure strip extends along the row direction, and the second ion-doped isolation structure strip extends along the column direction, or, the first ion-doped isolation structure strip extends along the column direction, and the second ion-doped isolation structure strip extends along the row direction.

14. The isolation structure of the image sensor according to claim 12, wherein Both the first gap and the second gap are rectangular or parallelogram-shaped; And / or, the region of each of the first ion-doped isolation structure strips corresponds to at least one of the second gaps, and the region of each of the second ion-doped isolation structure strips corresponds to at least one of the first gaps; And / or, the width of the first gap is greater than or equal to the width of the second ion-doped isolation structure strip, and the width of the second gap is greater than or equal to the width of the first ion-doped isolation structure strip.

15. The isolation structure of the image sensor according to any one of claims 12-14, characterized in that, At least two pixels under the same lens form a pixel unit for phase focusing. Among them, at least one focusing pitch is arranged between adjacent in-phase information acquisition pixels of the pixel unit, and the focusing pitch is formed based on the first gap and the corresponding second ion-doped isolation structure strip, or the focusing pitch is formed based on the second gap and the corresponding first ion-doped isolation structure strip.

16. The isolation structure of the image sensor according to claim 15, characterized in that, The included angle between the first ion-doped isolation structure strip and the second ion-doped isolation structure strip is less than 90°. One first ion-doped isolation structure strip and two second ion-doped isolation structure strips correspond to the same lens, or one second ion-doped isolation structure strip and two first ion-doped isolation structure strips correspond to the same lens.

17. An image sensor, characterized in that, Comprising the isolation structure according to any one of claims 12-16.

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