Photoresist pattern structure for improving photoresist pouring and method for improving photoresist pouring

Abstract

The invention provides a photoresist pattern structure for improving photoresist pouring and a method for improving photoresist pouring, the photoresist pattern structure comprises island-shaped structures, connection structures and openings, all the island-shaped structures are arranged in an array mode and are spaced from one another, the connection structures and the openings are respectively located in the gaps between the island-shaped structures, and the openings are located in the gaps between the island-shaped structures. And each island-shaped structure is connected with the adjacent island-shaped structure through at least one connecting structure. According to the invention, different island-shaped structures are connected by using at least one connecting structure, so that a supporting effect between the island-shaped structures is achieved, a photoresist pouring phenomenon is avoided, normal operation of a subsequent ion implantation process of a pixel region using a photoresist pattern structure as a mask is ensured, and the yield of the pixel region is improved. The condition of non-uniform ion implantation or abnormal implantation region is avoided, and the performance of the device is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a photoresist pattern structure for improving inverted photoresist and a method for improving inverted photoresist. Background Art

[0002] As the "eyes" of the mobile Internet world, smartphone image sensors have increasingly higher requirements for resolution, image quality, and power consumption. To further improve the resolution within the limited space of a mobile phone, the only way is to continuously reduce the pixel size while ensuring that the pixel sensitivity quality meets the design requirements.

[0003] The minimum pixel size of image sensors currently in mass production has reached 0.6μm to 0.7μm, and the small pixel process poses a great challenge to the high aspect ratio lithography process. Figure 1 , Figure 1 The present invention is a top view schematic diagram of a photoresist blocking structure used in an ion implantation process in a pixel region of an image sensor in the prior art. When the thickness requirement of a high aspect ratio photoresist for a current small pixel process reaches more than 3 μm and the pixel size is less than 1 μm, an opening pattern 12 is formed in the photoresist layer through photolithography processes such as exposure and development to obtain an island-shaped photoresist blocking structure 11. The island-shaped photoresist blocking structure 11 will have a serious photoresist backflow phenomenon, which will affect the subsequent ion implantation process in the pixel region, causing uneven ion implantation or abnormal implantation areas, thereby affecting device performance.

[0004] To address the problem of glue inversion, the industry usually adopts the Double Pattern process to improve the above glue inversion problem, but the Double Pattern process has some disadvantages, including: high cost, image mismatch caused by two alignments, and other problems. Summary of the invention

[0005] The present application provides a photoresist pattern structure for improving the inverted photoresist and a method for improving the inverted photoresist, which can solve the problem of serious inverted photoresist in the small pixel process of the image sensor, affecting the subsequent ion implantation and thus affecting the device performance.

[0006] On the one hand, the embodiment of the present application provides a photoresist pattern structure for improving the inverted photoresist, comprising: a plurality of island structures, a plurality of connecting structures and a plurality of openings, wherein all the island structures are arranged in an array and are spaced apart from each other, the connecting structures and the openings are respectively located in the spaces between the island structures, and each of the island structures is connected to an adjacent island structure through at least one connecting structure;

[0007] The photoresist pattern structure is a mask for the ion implantation process of the semiconductor structure at the bottom of the photoresist pattern structure, the intervals between the island structures are ion implantation regions of the semiconductor structure, and the openings are ion implantation windows of the semiconductor structure.

[0008] Optionally, in the photoresist pattern structure for improving photoresist backflow, the sum of the critical dimension of the island structure and the critical dimension of the opening along the width direction is less than 1 μm, and the thickness of the photoresist pattern structure is greater than 3 μm.

[0009] Optionally, in the photoresist pattern structure for improving the inversion of the photoresist, the line width of the connection structure is less than or equal to the critical dimension of the opening along the width direction.

[0010] Optionally, in the photoresist pattern structure for improving photoresist inversion, the island structure is polygonal, circular or elliptical.

[0011] Optionally, in the photoresist pattern structure for improving photoresist inversion, when the island structure is polygonal, the number of sides of the island structure is an even number.

[0012] Optionally, in the photoresist pattern structure for improving the inversion of the photoresist, when the island structure is polygonal, the connecting structure is located in the interval between the top corners of two adjacent island structures and / or in the interval between the straight sides of two adjacent island structures.

[0013] Optionally, in the photoresist pattern structure for improving the inversion of the photoresist, when the island structure is circular or elliptical, the connecting structure is located in the interval between any one or more arc edges of two adjacent island structures.

[0014] On the other hand, the present application also provides a method for improving photoresist pattern backfill, comprising:

[0015] Providing a semiconductor structure;

[0016] A photoresist pattern structure is formed on the semiconductor structure, and the photoresist pattern structure includes: a plurality of island structures, a plurality of connecting structures and a plurality of openings, wherein all the island structures are arranged in an array and are spaced apart from each other, the connecting structures and the openings are respectively located in the spaces between the island structures, and each of the island structures is connected to an adjacent island structure via at least one connecting structure; wherein the photoresist pattern structure is a mask for an ion implantation process of a semiconductor structure at the bottom of the photoresist pattern structure, the spaces between the island structures are ion implantation regions of the semiconductor structure, and the openings are ion implantation windows of the semiconductor structure.

[0017] Optionally, in the method for improving photoresist pattern backfill, the sum of the critical dimension of the island structure and the critical dimension of the opening along the width direction is less than 1 μm, and the thickness of the photoresist pattern structure is greater than 2 μm.

[0018] Optionally, in the method for improving the inverted photoresist pattern, after forming the photoresist pattern structure on the semiconductor structure, the method for improving the inverted photoresist pattern further comprises:

[0019] Using the photoresist pattern structure as a mask, the semiconductor structure is subjected to inclined ion implantation, with an inclination angle of 3° to 10°.

[0020] The technical solution of this application has at least the following advantages:

[0021] The present application provides a photoresist pattern structure for improving the inverted glue and a method for improving the inverted glue, wherein the photoresist pattern structure includes: an island structure, a connecting structure and an opening, wherein all the island structures are arranged in an array and are spaced apart from each other, the connecting structure and the opening are respectively located in the space between the island structures, and each island structure is connected to an adjacent island structure through at least one connecting structure. The present application connects different island structures by using at least one connecting structure, plays a supporting role between the island structures, avoids the inverted glue phenomenon of the photoresist, ensures the normal progress of the subsequent ion implantation process of the pixel area using the photoresist pattern structure as a mask, avoids the situation of uneven ion implantation or abnormal implantation area, improves device performance, avoids the situation of crosstalk of photogenerated electrons and / or noise electrons in each pixel area, improves the anti-crosstalk capability of the image sensor, improves the imaging color vividness of the image sensor, improves the image pixels, and improves the image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is a top view schematic diagram of a photoresist blocking structure used in an ion implantation process of a pixel region of an image sensor in the prior art;

[0024] Figure 2 is a top view schematic diagram of a first photoresist pattern structure according to an embodiment of the present invention;

[0025] Figure 3(a) is Figure 2A schematic cross-sectional view of the semiconductor structure along the AA' section line;

[0026] Figure 3(b) is Figure 2 A schematic cross-sectional view of the semiconductor structure along the BB' section line;

[0027] Figure 4 is a top view schematic diagram of a second photoresist pattern structure according to an embodiment of the present invention;

[0028] Figure 5 is a top view schematic diagram of a third photoresist pattern structure according to an embodiment of the present invention;

[0029] The reference numerals are described as follows:

[0030] 11- photoresist blocking structure; 12- opening pattern;

[0031] 21 - island structure, 22 - connection structure, 23 - opening, 30 - semiconductor structure. DETAILED DESCRIPTION

[0032] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0033] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0034] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0036] The present application embodiment provides a photoresist pattern structure for improving the backfilling, referring to Figure 2 , Figure 4 and Figure 5 The photoresist pattern structure for improving the inverted photoresist includes: a plurality of island structures 21, a plurality of connecting structures 22 and a plurality of openings 23, wherein all the island structures 21 are arranged in an array and are spaced apart from each other, the connecting structures 22 and the openings 23 are respectively located in the intervals between the island structures 21, and each of the island structures 21 is connected to an adjacent island structure 21 through at least one connecting structure 22.

[0037] 3(a) and 3(b), the photoresist graphic structure is a mask for the ion implantation process of the semiconductor structure 30 at the bottom of the photoresist graphic structure, the intervals between the island structures 21 are ion implantation regions of the semiconductor structure, and the openings 23 are ion implantation windows of the semiconductor structure.

[0038] Preferably, the sum of the critical dimensions of any one of the island structures 21 and the critical dimensions of one of the openings 23 on the side of the island structure 21 along the width direction is less than 1 μm, and the thickness of the photoresist pattern structure is greater than 3 μm. The critical dimensions of the island structure are the critical dimensions of the island structure along the width direction or the critical dimensions of the island structure along the length direction. In addition, it is worth noting that the critical dimensions of the opening 23 are mainly divided into: the critical dimensions along the width direction and the critical dimensions along the length direction. In this embodiment, the shorter side length of the opening 23 is defined as the width, and the longer side length of the opening 23 is defined as the length.

[0039] Furthermore, the line width of the connection structure 22 is smaller than or equal to the critical dimension of the opening along the width direction.

[0040] In this embodiment, the line width of the connection structure 22 is 0.1 μm to 0.2 μm.

[0041] Preferably, the island structure 21 is polygonal, circular or elliptical.

[0042] Preferably, when the island-like structures 21 are polygonal, the connecting structures 22 are located in the interval between the apex corners of two adjacent island-like structures 21 and / or in the interval between the straight sides of two adjacent island-like structures 21 .

[0043] Furthermore, when the island structure 21 is polygonal, the number of sides of the island structure 21 is an even number.

[0044] In this embodiment, the island structure 21 is rectangular.

[0045] refer to Figure 2 3(a) and 3(b), the connection structure 22 is located in the intervals between all the vertex corners of each of the island-like structures 21. Each of the island-like structures 21 is connected to its adjacent island-like structures 21 through the connection structure 22 between all the vertex corners of each of the island-like structures 21.

[0046] refer to Figure 4 The connecting structure 22 is located in the interval between two opposite vertex corners of each of the island structures 21 .

[0047] refer to Figure 5 , the connecting structure 22 is located in the interval between the straight sides of each of the island structures 21 .

[0048] Furthermore, the connection structure 22 may also be located in the interval between the top corners of two adjacent island structures 21 and in the interval between the straight sides of the island structures 21 (not shown).

[0049] Furthermore, when the island-like structures 21 are circular or elliptical, the connecting structure 22 is located in the interval between any one or more arc edges of two adjacent island-like structures 21 .

[0050] Based on the same inventive concept, the present application also provides a method for improving the photoresist pattern backfill, referring to Figure 2 , Figure 3(a) and Figure 3(b) and Figure 4-5 , the method for improving the photoresist pattern backfill includes:

[0051] Step S1: providing a semiconductor structure 30;

[0052] Step S2: forming a photoresist pattern structure on the semiconductor structure 30, wherein the photoresist pattern structure comprises: a plurality of island structures 21, a plurality of connecting structures 22 and a plurality of openings 23, wherein all the island structures 21 are arranged in an array and are spaced apart from each other, the connecting structures 22 and the openings 23 are respectively located in the spaces between the island structures 21, and each of the island structures 21 is connected to an adjacent island structure 21 via at least one connecting structure 22; wherein the photoresist pattern structure is a mask for an ion implantation process of the semiconductor structure 30 at the bottom of the photoresist pattern structure, the spaces between the island structures 21 are ion implantation regions of the semiconductor structure 30, and the openings 23 are ion implantation windows of the semiconductor structure.

[0053] It is worth noting that the photoresist pattern structure is obtained by performing photolithography processes such as exposure and development on the photoresist layer. Further, the semiconductor structure 30 can be a film layer structure of a pixel region of a conventional image sensor, and the present application does not impose any restrictions on the material, thickness and other parameters of the specific film layer of the semiconductor structure 30.

[0054] Preferably, the sum of the critical dimension of any one of the island structures 21 and the critical dimension of one of the openings 23 on the side of the island structure 21 along the width direction is less than 1 μm, and the thickness of the photoresist pattern structure is greater than 2 μm.

[0055] Furthermore, after forming a photoresist graphic structure on the semiconductor structure, the method for improving the photoresist graphic backfill may also include: Step S3: using the photoresist graphic structure as a mask, performing inclined ion implantation on the semiconductor structure 30, with an inclination angle of 3° to 10°, wherein this embodiment defines the angle between the ion incident direction and the vertical direction as the inclination angle of ion implantation.

[0056] It is worth noting that the island structure 21 is used to block the ion implantation in the corresponding area of ​​the semiconductor structure 30 at the bottom thereof, so that no ions are doped in the spatially completely overlapping area at the bottom of the island structure 21, thereby achieving the isolation of the pixel area of ​​the image sensor, isolating the photogenerated electrons and / or noise electrons in the gaps between the island structures 21, and avoiding the crosstalk of the photogenerated electrons and / or noise electrons in the substrate area of ​​each pixel area.

[0057] In this embodiment, the semiconductor structure 30 can be tilted and implanted with P-type ions using the photoresist pattern structure as a mask, with an inclination angle of 3° to 10°. The P-type ion implantation is tilted, and there will be a certain amount of lateral diffusion after the ion implantation, and a thermal annealing process can be performed laterally to enhance the lateral diffusion of the P-type ions in the semiconductor structure 30, so that the P-type ion implantation areas isolated by the connection structure 22 can be connected, thereby forming an electrical grid in the semiconductor structure 30, wherein the interval between the finally formed ion implantation area and the island structure 21 completely overlaps in space.

[0058] In the present application, different island structures are connected by using at least one connecting structure, which plays an effective supporting role between the island structures, avoids the phenomenon of photoresist backflow, ensures the normal progress of the subsequent ion implantation process of the pixel area using the photoresist graphic structure as a mask, avoids the crosstalk of photogenerated electrons and / or noise electrons in each pixel area, improves the anti-crosstalk capability of the image sensor, improves the imaging color vividness of the image sensor, increases the image pixels, and improves the image quality.

[0059] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection created by this application.

Claims

1. A photoresist pattern structure for improving the inverted photoresist, characterized in that: include: A plurality of island structures, a plurality of connecting structures and a plurality of openings, wherein all the island structures are arranged in an array and are spaced apart from each other, the connecting structures and the openings are respectively located in the spaces between the island structures, and each of the island structures is connected to an adjacent island structure via at least one connecting structure; The photoresist pattern structure is a mask for the ion implantation process of the semiconductor structure at the bottom of the photoresist pattern structure, the intervals between the island structures are ion implantation regions of the semiconductor structure, and the openings are ion implantation windows of the semiconductor structure.

2. The photoresist pattern structure for improving the inverted photoresist according to claim 1, characterized in that: The sum of the critical dimension of the island structure and the critical dimension of the opening along the width direction is less than 1 μm, and the thickness of the photoresist pattern structure is greater than 3 μm.

3. The photoresist pattern structure for improving the inversion of the photoresist according to claim 2, characterized in that: The line width of the connection structure is less than or equal to the critical dimension of the opening along the width direction.

4. The photoresist pattern structure for improving the inversion of the photoresist according to claim 1, characterized in that: The island structure is polygonal, circular or elliptical.

5. The photoresist pattern structure for improving the inverted photoresist according to claim 4, characterized in that: When the island-like structure is polygonal, the number of sides of the island-like structure is an even number.

6. The photoresist pattern structure for improving the inverted photoresist according to claim 5, characterized in that: When the island-like structures are polygonal, the connecting structures are located in the interval between the vertex corners of two adjacent island-like structures and / or in the interval between the straight sides of two adjacent island-like structures.

7. The photoresist pattern structure for improving the inversion of the photoresist according to claim 4, characterized in that: When the island-like structures are circular or elliptical, the connecting structure is located in the interval between any one or more arc edges of two adjacent island-like structures.

8. A method for improving photoresist pattern backfill, characterized in that: include: Providing a semiconductor structure; A photoresist pattern structure is formed on the semiconductor structure, and the photoresist pattern structure includes: a plurality of island structures, a plurality of connecting structures and a plurality of openings, wherein all the island structures are arranged in an array and are spaced apart from each other, the connecting structures and the openings are respectively located in the spaces between the island structures, and each of the island structures is connected to an adjacent island structure via at least one connecting structure; wherein the photoresist pattern structure is a mask for an ion implantation process of a semiconductor structure at the bottom of the photoresist pattern structure, the spaces between the island structures are ion implantation regions of the semiconductor structure, and the openings are ion implantation windows of the semiconductor structure.

9. The method for improving photoresist pattern backfill according to claim 8, characterized in that: The sum of the critical dimension of the island structure and the critical dimension of the opening along the width direction is less than 1 μm, and the thickness of the photoresist pattern structure is greater than 2 μm.

10. The method for improving photoresist pattern backfill according to claim 8, characterized in that: After forming a photoresist pattern structure on the semiconductor structure, the method for improving the photoresist pattern backfill further comprises: Using the photoresist pattern structure as a mask, the semiconductor structure is subjected to inclined ion implantation, with an inclination angle of 3° to 10°.

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