Photomask plate

Abstract

This application discloses a photomask template, including a photomask body. The photomask body includes a transparent substrate, a phase-shifting layer, and a light-shielding layer stacked together. The transparent substrate is located between the phase-shifting layer and the light-shielding layer, or the transparent substrate is located on the side of the phase-shifting layer away from the light-shielding layer, or the transparent substrate is located on the side of the light-shielding layer away from the phase-shifting layer. The photomask body includes multiple light-blocking regions and an exposure region between the light-blocking regions, and a light compensation pattern is disposed in the exposure region. The above scheme improves the light intensity on the light-emitting side of the photomask.

Description

Technical Field

[0001] This invention generally relates to the field of photomask technology, and specifically to a photomask. Background Technology

[0002] Photomasks are used in the manufacturing processes of electronic devices such as display devices and semiconductor integrated circuits. Photomasks have transfer patterns, which are transferred onto a target substrate, such as a photoresist layer, by exposure light, forming the corresponding pattern. As the internal structures of electronic devices become increasingly sophisticated, the width of at least some exposure areas in the photomask is becoming narrower. In some cases, the light intensity reaching the target substrate through this area is insufficient, resulting in inadequate exposure of the target substrate and insufficient pattern thickness. Summary of the Invention

[0003] This application aims to provide a photomask template for increasing the light intensity transmitted through at least a portion of the photomask.

[0004] The present invention provides a photomask template, including a photomask body, the photomask body including a transparent substrate, a phase shift layer and a light shielding layer stacked thereon; the transparent substrate is located between the phase shift layer and the light shielding layer, or the transparent substrate is located on the side of the phase shift layer away from the light shielding layer, or the transparent substrate is located on the side of the light shielding layer away from the phase shift layer;

[0005] The photomask body includes multiple light-blocking areas and an exposure area between the light-blocking areas, and a light compensation pattern is provided in the exposure area.

[0006] As one possible implementation, the phase-shifting layer includes a non-phase-shifted region and a phase-shifted region surrounding the non-phase-shifted region, the phase-shifted region being used to generate a phase shift in a portion of the exposed light within the exposure region;

[0007] The light shielding layer includes multiple light-blocking patterns and the light compensation pattern. Each light-blocking pattern is used to define the light-blocking area, and the area between the light-blocking patterns is used to define the exposure area. The multiple light-blocking patterns are arranged in an array along intersecting first and second directions. In the first direction, the distance between adjacent light-blocking patterns is smaller than the distance between adjacent light-blocking patterns in the second direction. The light compensation pattern is located between adjacent light-blocking patterns in the first direction.

[0008] As an implementation, the orthogonal projection of the exposed region on the transparent substrate covers the orthogonal projection of the non-phase-shifted region on the transparent substrate;

[0009] The orthogonal projection of the exposure area on the transparent substrate covers a portion of the orthogonal projection of the phase-shifting area on the transparent substrate;

[0010] The orthogonal projection of the phase-shifting region on the transparent substrate overlaps the orthogonal projection of the light-blocking pattern on the transparent substrate.

[0011] As one possible implementation, in the first direction, the phase-shifted region is located at the boundary of the exposure region, and the distance between it and the boundary of the adjacent light-blocking pattern is A:

[0012] A = (bce) / 2;

[0013] Where b is the distance between adjacent light-blocking patterns in the first direction, c is the width of the transfer pattern corresponding to the exposure area in the first direction, and e is the width of the light compensation pattern in the first direction.

[0014] As an implementation method, the side of the light compensation pattern parallel to the second direction is shorter than the side of the light blocking pattern parallel to the second direction.

[0015] As an implementation method, the distance between the side of the light compensation pattern parallel to the first direction and the side of the corresponding light blocking pattern parallel to the first direction in the second direction is 1-10 μm.

[0016] As an implementation, in the second direction, the length of the light compensation pattern is less than the length of the light blocking pattern, and in an orthographic projection perpendicular to the second direction, the light blocking pattern covers the light compensation pattern.

[0017] As an implementation method, in the second direction, the distance between the apex corner of any end of the light-blocking pattern and the corresponding end of the light-compensating pattern is 1-10 μm; the apex corner is the angle closest to the corresponding end of the light-compensating pattern.

[0018] As an implementation, the orthographic projection of the light compensation pattern on the transparent substrate is located in the middle of the orthographic projection of the exposure area on the transparent substrate.

[0019] As an implementation method, the light compensation pattern is a strip pattern extending in the second direction.

[0020] As an implementation method, the width of the light compensation pattern in the first direction is 0.5-1.5 μm.

[0021] As an implementation method, the phase-shifting layer is used to cause a phase shift of 180°±60° in a portion of the exposed light within the exposure area.

[0022] The above scheme, by setting a compensation pattern, divides the exposure light in the exposure area into two beams of light on both sides of the compensation pattern. In addition, due to the setting of a phase shift layer, the phase shift layer is used to induce a phase shift in some of the exposure light in the exposure area, while the other part of the exposure light does not undergo a phase shift. Under the action of light wave interference and / or diffraction, the amplitude value and frequency of the light passing through the photomask in the exposure area increase, thereby increasing the light intensity on the light-emitting side of the photomask. As the light intensity in the exposure area increases, the target substrate can be fully exposed, ensuring that the formed pattern has sufficient thickness. Attached Figure Description

[0023] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0024] Figure 1 A three-dimensional schematic diagram of the exposure process for related technologies;

[0025] Figure 2 for Figure 1 The main view;

[0026] Figure 3 for Figure 1 EE sectional view;

[0027] Figure 4 This is a top view of the photomask template provided in Embodiment 1 of the present invention;

[0028] Figure 5 for Figure 4 A FF cross-sectional view showing the usage status of a photomask template;

[0029] Figure 6 This is a schematic diagram of the fabrication process of the photomask template provided in Embodiment 1 of the present invention;

[0030] Figure 7 This is a schematic diagram of the structure of the photomask template provided in Embodiment 2 of the present invention;

[0031] Figure 8 This is a schematic diagram of the fabrication process of the photomask template provided in Embodiment 2 of the present invention;

[0032] Figure 9 This is a schematic diagram of the structure of the photomask template provided in Embodiment 3 of the present invention.

[0033] Figure 10 This is a schematic diagram of the fabrication process of the photomask template provided in Embodiment 3 of the present invention;

[0034] Figure 11 A comparison diagram of the phase and light intensity of the photomask template provided for embodiments of the present invention;

[0035] Figure 12 The light intensity distribution cloud map of the compensation pattern without shrinkage is provided in an embodiment of the present invention;

[0036] Figure 13 A light intensity distribution cloud map after the compensation pattern is retracted by a predetermined distance, provided as an embodiment of the present invention;

[0037] Figure 14 A thickness comparison diagram of the exposure patterns formed by the related technology provided in the embodiments of the present invention and the photomask template of the present invention in the same exposure process. Detailed Implementation

[0038] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] In related technologies, such as the manufacturing processes of electronic devices like display devices and semiconductor integrated circuits, exposure is an essential step. Exposure involves using a photomask to expose a photoresist layer and then developing the exposed photoresist layer to form a corresponding pattern. In other words, the exposure process replicates the pattern on the photomask onto the photoresist layer with minimal distortion. How to replicate the pattern on the photomask with minimal distortion is directly related to the resolution of the exposure optical system. To improve resolution, related technologies employ off-axis illumination (OAI), phase-shift mask (PSM), or optical proximity correction (OPC) techniques. However, referring to… Figure 1 Whether it is OAI technology, PSM technology, or OPC technology, they all only change the distribution of light intensity in the plane along the XY axis to improve exposure resolution. However, the inventors of this application have discovered that even if any of the above technologies are used, there is still a problem of insufficient thickness (topless) in the Z axis direction.

[0041] Specifically, see Figure 1As shown, for example, when fabricating a color filter substrate for a display device, proximity exposure is generally used to expose the photoresist layer used to form the black matrix (BM). Due to the proximity exposure, a tiny gap is left between the photomask and the photoresist layer. This gap is, for example, but not limited to, 10 μm to 200 μm. Figure 1 In this context, the photomask pattern is a rectangular light-blocking pattern 21. Depending on the actual needs, the light-blocking pattern 21 can also be other shapes, such as the irregular shapes described below; see also... Figure 2 As shown, under the influence of gravity, the center of the photomask will have a certain amount of concavity. This causes the distance from the edge of the photomask to the photoresist layer forming the black matrix BM to be greater than the distance from the center of the photomask to the photoresist layer forming the black matrix BM. In other words, the optical path from the edge of the photomask to the photoresist layer is greater than the optical path from the center of the photomask to the photoresist layer. As the optical path increases, the optical loss also increases accordingly. Consequently, the light intensity of the exposure light 4 reaching the corresponding position of the photoresist layer will decrease, resulting in insufficient exposure of the photoresist in the corresponding area. This leads to the black matrix BM formed after development being... Figure 3 As shown, there is a problem of insufficient thickness (topless) in the Z-axis direction at the insufficiently exposed position, which causes light leakage in the display device L0 (dark state display, i.e., 0 gray level) using this color filter substrate.

[0042] To increase the light intensity reaching the photoresist layer and ensure sufficient exposure to overcome the topless problem, this patent provides the following photomask template technical solution. (See at least [reference needed]). Figure 4 , Figure 5 The photomask includes a photomask body, which comprises a transparent substrate 3, a phase-shifting layer 1, and a light-shielding layer 2 stacked together. The transmittance of the transparent substrate 3 to the exposure light 4 is, for example, but not limited to, greater than 95%. The stacked transparent substrate 3, phase-shifting layer 1, and light-shielding layer 2 can be configured in three ways: the transparent substrate 3 is located between the phase-shifting layer 1 and the light-shielding layer 2; the transparent substrate 3 is located on the side of the phase-shifting layer 1 away from the light-shielding layer 2; or the transparent substrate 3 is located on the side of the light-shielding layer 2 away from the phase-shifting layer 1. Any two adjacent layers of the stacked transparent substrate 3, phase-shifting layer 1, and light-shielding layer 2 can be in direct contact, or other layer structures can be provided between any two adjacent layers. In this paper, the example of any two adjacent layers of the transparent substrate 3, phase-shifting layer 1, and light-shielding layer 2 being in direct contact is used for illustration. The photomask body includes multiple light-blocking regions and an exposure region 23 between the light-blocking regions. A light compensation pattern 22 is provided within the exposure region 23.

[0043] The "patterning process" mentioned in this article includes deposition of film layers, coating with photoresist, mask exposure, development, etching, and photoresist stripping, which are mature fabrication processes in related technologies. The "photolithography process" mentioned in this article includes coating of film layers, mask exposure, and development, which are mature fabrication processes in related technologies. Deposition can employ known processes such as sputtering, evaporation, and chemical vapor deposition; coating can employ known coating processes; and etching can employ known methods, without specific limitations here. In the descriptions in this article, it is important to understand that a "thin film" refers to a thin film of a certain material fabricated on a substrate using deposition or coating processes. If the "thin film" does not require patterning or photolithography processes during the entire fabrication process, it can also be called a "layer." If the "thin film" requires patterning or photolithography processes during the entire fabrication process, it is called a "thin film" before the patterning process and a "layer" after the patterning process. A "layer" after the patterning or photolithography process contains at least one "pattern."

[0044] At least see Figure 4 , Figure 5 As shown in the embodiment of the present invention, a photomask includes a photomask body, which includes a transparent substrate 3, a phase shift layer 1, and a light shielding layer 2 stacked together. The transparent substrate 3 is located on the side of the light shielding layer 2 away from the phase shift layer 1. Furthermore, the photomask body includes a plurality of light-blocking regions and an exposure region 23 between the light-blocking regions. A light compensation pattern 22 is disposed in the exposure region 23.

[0045] The transparent substrate 3 is, for example, but not limited to, quartz glass.

[0046] As one possible implementation, the phase-shifting layer 1 includes a non-phase-shifting region 12 and a phase-shifting region 11 surrounding the non-phase-shifting region 12, the phase-shifting region 11 being used to generate a phase shift for a portion of the exposure light 4 within the exposure region 23.

[0047] In this scheme, the phase-shifted region 11 refers to the region where the phase of the exposure light 4 can change as it passes through the phase-shifted layer 1, and the non-phase-shifted region 12 refers to the region where the phase of the exposure light 4 does not change as it passes through the phase-shifted layer 1.

[0048] It can be that a phase-shifting film is deposited on the light-shielding film used to form the light-shielding layer 2, and the phase-shifting film is patterned to form a phase-shifting layer 1 having a non-phase-shifting region 12 and a phase-shifting region 11 surrounding the non-phase-shifting region 12.

[0049] Materials used for depositing phase-shifted thin films include silicon-containing materials, such as silicides of at least one of transition metals, oxygen, nitrogen, and carbon; in this example, silicon dioxide is used.

[0050] The transition metal can be at least one element selected from titanium, vanadium, cobalt, nickel, zirconium, niobium, molybdenum, hafnium, tantalum, and tungsten.

[0051] The amount of phase shift of the phase shift layer 1 on the exposure light 4 is related to its thickness. The amount of phase shift of the phase shift layer 1 on the exposure light 4 can be controlled by selecting phase shift layers 1 with different thicknesses.

[0052] The thickness of phase-shifting layer 1 and the phase shift of exposure light 4 satisfy the following relationship:

[0053] T = λ / 2(n + cosθ);

[0054] Where T is the thickness of phase-shifting layer 1, λ is the wavelength of exposure light 4, n is the refractive index of phase-shifting layer 1, and θ is the phase shift amount.

[0055] For the phase-shifting layer, the orthogonal projection of the exposure area 23 on the transparent substrate 3 overlaps with the orthogonal projection of the non-phase-shifting area 12 on the transparent substrate 3; the orthogonal projection of the exposure area 23 on the transparent substrate 3 partially overlaps with the orthogonal projection of the phase-shifting area 12 on the transparent substrate 3; the orthogonal projection of the phase-shifting area 11 on the transparent substrate 3 overlaps with the orthogonal projection of the light-blocking pattern 21 on the transparent substrate 3; that is, the non-phase-shifting area 12 is completely located within the exposure area 23, and a portion of the phase-shifting area 11 protrudes into the exposure area 23. The phase-shifting area 11 protruding into the exposure area 23 causes a phase shift in some of the exposed light rays 4.

[0056] The light shielding layer 2 includes a plurality of light blocking patterns 21 and light compensation patterns 22. Each light blocking pattern 21 is used to define the light blocking area, and the area between the light blocking patterns 21 is used to define the exposure area 23.

[0057] The photomask template in this example can be used for films that require exposure to form, such as black matrices and spacers. For example, it can be used to prepare a black matrix BM, where the light-blocking pattern 21 corresponds to the opening of the sub-pixel in the black matrix BM. This photomask template is used to expose and develop negative photoresist to prepare the black matrix BM.

[0058] The light shielding layer 2 is, for example, a light shielding film deposited on a transparent substrate 3 and patterned.

[0059] Materials used for depositing light-shielding films include, but are not limited to, chromium (Cr) and chromium compounds.

[0060] As one possible implementation, the compensation pattern 22 can be a strip pattern located in a direction where the spacing between two different arrangement directions of adjacent light-blocking patterns 21 is small. For example, the light-blocking patterns 21 on the photomask are arranged in an array, and the spacing between adjacent light-blocking patterns 21 may be different in different directions. For example, multiple light-blocking patterns 21 are arranged in an array along an intersecting first direction (X-axis direction) and a second direction (Y-axis direction). Of course, in other examples, the first and second directions may not be perpendicular to each other. In the first direction, the distance between adjacent light-blocking patterns 21 is smaller than the distance between adjacent light-blocking patterns 21 in the second direction. The light compensation pattern 22 is located between adjacent light-blocking patterns 21 in the first direction. The light intensity corresponding to the position with small spacing will be relatively low. By setting the light compensation pattern 22, the exposure light 4 in this area is split to cause interference and / or diffraction, thereby increasing the light intensity at the corresponding position.

[0061] For example, the first direction can be the row direction, and the second direction can be the column direction.

[0062] The light compensation pattern 22 is a strip-shaped pattern extending in the second direction. By setting the light compensation pattern 22 with a strip-shaped pattern, the light intensity can be increased across the entire area between adjacent light-blocking patterns 21.

[0063] The above scheme, by setting a compensation pattern, divides the exposure light 4 in the exposure area 23, which can be regarded as being divided into two beams of light on both sides of the light compensation pattern 22. In addition, since a phase shift layer 1 is set, the phase shift layer 1 is used to generate a phase shift for some of the exposure light 4 in the exposure area 23, while the other part of the exposure light 4 does not undergo a phase shift. Under the action of light wave interference and / or diffraction, the amplitude value and frequency of the light passing through the photomask in the exposure area 23 increase, thereby increasing the light intensity on the light-emitting side of the photomask. As the light intensity in the exposure area 23 increases, the target substrate can be fully exposed, ensuring that the formed pattern has sufficient thickness.

[0064] like Figure 6 As shown, the photomask with the above structure can be fabricated in the following manner. This fabrication method is only illustrative and only shows the final transparent substrate 3, phase shift layer 1, and light shielding layer 2. If etching of the blocking layer, film transfer, etc., are required during fabrication, they can be set according to actual needs and will not be listed here:

[0065] S1: Provides a transparent substrate 3;

[0066] S2: Deposit a Cr thin film 222 on the transparent substrate 3;

[0067] S3: Deposit SiO2 film 111 on Cr film 222;

[0068] S4: Pattern the SiO2 thin film 111, etch away a portion of the SiO2 material, and form a phase-shifting layer 1 including a non-phase-shifting region 12 and a phase-shifting region 11 surrounding the non-phase-shifting region 12;

[0069] S5: Pattern the Cr thin film 222, etch away a portion of the Cr material, and form a light shielding layer 2 having multiple light-blocking patterns 21 and an exposure area 23 surrounding each light-blocking pattern 21, as well as a light compensation pattern 22 located within the exposure area 23; and ensuring that the orthogonal projection of the exposure area 23 on the transparent substrate 3 covers the orthogonal projection of the non-phase-shifted region 12 on the transparent substrate 3; the orthogonal projection of the exposure area 23 on the transparent substrate 3 covers a portion of the orthogonal projection of the phase-shifted region 11 on the transparent substrate 3; the orthogonal projection of the phase-shifted region 11 on the transparent substrate 3 covers the orthogonal projection of the light-blocking pattern 21 on the transparent substrate 3; and the orthogonal projection of the light compensation pattern 22 on the transparent substrate 3 is located in the middle of the orthogonal projection of the exposure area 23 on the transparent substrate 3.

[0070] like Figure 7 As shown, the main difference between this example and the example above is that the transparent substrate 3 is located between the phase shift layer 1 and the light shielding layer 2.

[0071] See also at least Figure 8 As shown, the photomask template of this example structure can be fabricated in the following manner:

[0072] S1: Provides a transparent substrate 3;

[0073] S2: Deposit a Cr thin film 222 on the transparent substrate 3;

[0074] S3: Pattern the Cr thin film 222, etch away a portion of the Cr material, and form a light shielding layer 2 having multiple light-blocking patterns 21 and an exposure area 23 surrounding each light-blocking pattern 21, as well as a light compensation pattern 22 located within the exposure area 23.

[0075] S4: Flip the transparent substrate 3 180° and deposit a SiO2 thin film 111 on the side of the transparent substrate 3 away from the light shielding layer 2;

[0076] S5: Pattern the SiO2 thin film 111, etch away a portion of the SiO2 material, and form a phase-shifting layer 1 including a non-phase-shifting region 12 and a phase-shifting region 11 surrounding the non-phase-shifting region 12; and ensure that the orthogonal projection of the exposure region 23 on the transparent substrate 3 covers the orthogonal projection of the non-phase-shifting region 12 on the transparent substrate 3; the orthogonal projection of the exposure region 23 on the transparent substrate 3 covers a portion of the orthogonal projection of the phase-shifting region 11 on the transparent substrate 3; the orthogonal projection of the phase-shifting region 11 on the transparent substrate 3 covers the orthogonal projection of the light-blocking pattern 21 on the transparent substrate 3; the orthogonal projection of the light-compensating pattern 22 on the transparent substrate 3 is located in the middle of the orthogonal projection of the exposure region 23 on the transparent substrate 3.

[0077] In this example, the light shielding layer 2 is first prepared on one side of the transparent substrate 3, and then the phase shifting layer 1 is prepared on the other side of the transparent substrate 3. Of course, in other examples, the phase shifting layer 1 can be prepared on one side of the transparent substrate 3 first, and then the light shielding layer 2 can be prepared on the other side of the transparent substrate 3.

[0078] like Figure 9 As shown, the main difference between this example and the example above is that the transparent substrate 3 is located on the side of the phase shift layer 1 away from the light shielding layer 2.

[0079] See also at least Figure 10 As shown, the photomask template of this example structure can be fabricated in the following manner:

[0080] S1: Provides a transparent substrate 3;

[0081] S2: Deposit a SiO2 thin film 111 on the transparent substrate 3;

[0082] S3: Deposit Cr film 222 on SiO2 film 111;

[0083] S4: Pattern the Cr thin film 222, etch away a portion of the Cr material to form a light shielding layer 2 with multiple light-blocking patterns 21 and an exposure area 23 surrounding each light-blocking pattern 21, and a light compensation pattern 22 in the exposure area 23 between adjacent light-blocking patterns 21.

[0084] S5: Pattern the SiO2 thin film 111, etch away a portion of the SiO2 material, and form a phase-shifting layer 1 including a non-phase-shifting region 12 and a phase-shifting region 11 surrounding the non-phase-shifting region 12; and ensure that the orthogonal projection of the exposure region 23 on the transparent substrate 3 covers the orthogonal projection of the non-phase-shifting region 12 on the transparent substrate 3; the orthogonal projection of the exposure region 23 on the transparent substrate 3 covers a portion of the orthogonal projection of the phase-shifting region 11 on the transparent substrate 3; the orthogonal projection of the phase-shifting region 11 on the transparent substrate 3 covers the orthogonal projection of the light-blocking pattern 21 on the transparent substrate 3; the orthogonal projection of the light-compensating pattern 22 on the transparent substrate 3 is located in the middle of the orthogonal projection of the exposure region 23 on the transparent substrate 3.

[0085] See also Figure 11 As shown, Figure 11 In the image, the left side shows a photomask without the phase-shifting layer 1 and the light compensation pattern 22 in related technologies, along with the phase distribution and intensity distribution of the exposure light ray 4 as it passes through the photomask and reaches the photoresist layer. The right side shows a photomask with the phase-shifting layer 1 and the light compensation pattern 22 in this invention, along with the phase distribution and intensity distribution of the exposure light ray 4 as it passes through the photomask and reaches the photoresist layer. Figure 11 It is easy to see that after the exposure ray 4 passes through the portion of the phase-shifted region 11 that protrudes into the exposure region 23, the phase changes, resulting in a 180° phase shift in this example. Figure 11 In the middle, T1 becomes T2; the light rays that are divided by the light compensation pattern 22 and do not pass through the phase shift region 11 interfere with each other and superimpose, thereby increasing the amplitude and frequency of the light rays in the non-phase shift region 12; and the light rays in the phase shift region 11 and the non-phase shift region 12 produce destructive interference due to their different phases, thereby changing the spatial light intensity distribution. Under the condition that the light source emitting the exposure light 4 remains unchanged, the light intensity reaching the photoresist layer is improved.

[0086] As an implementation method, the phase shift region 11 is used to cause the exposure light 4 passing through the phase shift region 11 to produce a phase shift of 180°±60°.

[0087] As an implementation method, the exposure light 4 exhibits wave properties, and the phase shift is 180°, which can maximize the light intensity by superimposing the phase-shifted exposure light 4 with the non-phase-shifted exposure light 4.

[0088] Generally, the shape and position of the light compensation pattern 22 need to be determined according to the specific shape of the light blocking pattern 21. The inventor of this patent discovered that after determining the light compensation pattern 22 according to the specific shape of the light blocking pattern 21, a certain amount of retraction is made at both ends of the light compensation pattern 22, which can achieve a better effect in increasing light intensity.

[0089] That is, the side of the light compensation pattern 22 parallel to the second direction is shorter than the side of the light blocking pattern 21 parallel to the second direction. Here, "side" can be understood as the overall length of the light compensation pattern 22 and the light blocking pattern 21 extending in the second direction, and does not uniquely refer to a single edge of the light compensation pattern 22 or the light blocking pattern 21. In other words, in the second direction, the light compensation pattern 22 is shorter than the light blocking pattern 21.

[0090] As an implementation, the distance between the side of the light compensation pattern 22 parallel to the first direction and the side of the corresponding light-blocking pattern 21 parallel to the first direction in the second direction is 1-10 μm. That is, in the second direction, the light compensation pattern 22 is retracted by 1-10 μm relative to the light-blocking pattern 21.

[0091] For example, the light-blocking pattern 21 can be a rectangle, a regular polygon, an irregular polygon, etc. When the light-blocking pattern 21 is a rectangle, the light compensation pattern 22 can also be a rectangle. In this case, the "side" mentioned above refers to the long side of the rectangle, that is, the long side of the light compensation pattern 22 is shorter than the long side of the light-blocking pattern 21.

[0092] Figure 4 In the example shown, the light-blocking pattern 21 is an irregular polygon. In the second direction, the length of the compensation pattern is less than the length of the light-blocking pattern, and in the orthographic projection perpendicular to the second direction, the compensation pattern covers the light-blocking pattern; that is, the two ends of the compensation pattern 22 are retracted by a certain amount relative to the two ends of the light-blocking pattern 21.

[0093] Specifically, in the second direction, the distance L between the apex D of the end of the light-blocking pattern 21 and the nearest apex of the compensation pattern 22 and the corresponding end of the compensation pattern 22 is 1-10 μm, that is, the retraction distance L is 1-10 μm; for example, but not limited to, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, etc.

[0094] like Figure 12 As shown, after determining the shape and position of the light compensation pattern 22 based on the specific shape of the light-blocking pattern 21, the light intensity is reduced at both edges of the light compensation pattern 22 when viewed from the cross-sectional view at the location where the light compensation pattern 22 is set; Figure 13 As shown, the inventors of this patent retracted the two ends of the light compensation pattern 22 by a certain amount. For example, the retraction distance L is 6μm. After retraction, the light intensity at the edges of the two ends of the light compensation pattern 22 is increased.

[0095] The light compensation pattern 22 can be determined based on the specific shape of the light-blocking pattern 21, and can be done in the following way:

[0096] For a photomask, it has only an exposure area 23 (which can be fully transparent or partially transparent depending on the transmittance) and an opaque light-blocking pattern 21. Define f(x) as the input function and h(x) as the output function, where f(x) = 1 indicates light transmission and f(x) = 0 indicates opaqueness or partial light transmission.

[0097] Divide the photomask into multiple small grids, using a ij This indicates whether the cell in the i-th row and j-th column is transparent, where i and j are natural numbers;

[0098]

[0099] Where d is the variable length of the small grid, and rent(x,y) is the rectangular signal function;

[0100] If g(x,y) is the response of the optical system to rect(x,y), then according to the properties of the limiting system, we have:

[0101]

[0102] If the exposure ray 4 is partially coherent, then the spectrum function of the impulse function δ(x,y) after passing through the optical system of this exposure is:

[0103] G(f,h)=∫∫TCC·δ·δ′df′dg′;

[0104] Where TCC is the transfer function;

[0105] In this optical system, the input light intensity is the sum of impulse functions, then:

[0106] f(x,y)=∑∑a ij δ ij (x,y);

[0107] Therefore, the final output light intensity is:

[0108] I(x,y)=∑∑a ij g(x-id,y-jd);

[0109] Where g(x,y) is the Fourier inverse transform of G(f,h);

[0110] In the above output light intensity, a ij It is the small cell in the i-th row and j-th column, which is binary and indicates whether the corresponding small cell is transparent. Therefore, it can be determined by a. ij Determine the shape and position of the compensation pattern 22, and then retract both ends of the compensation pattern 22 determined according to the above relationship, as shown above. The retraction distance can be 1-10μm.

[0111] As an feasible approach, for example, under process conditions of 35 mJ exposure, a gap of 170 μm between the photomask and photoresist, a transmittance of 5.2% for the phase-shifting layer 1, a phase shift of 180°, and a width e of 1 μm for the light compensation pattern 22, the exposure intensity is significantly improved when both ends of the light compensation pattern 22 are retracted by 6 μm, i.e., when the aforementioned distance L is 6 μm. The exposure intensity increases from 0.514 to 0.726, an increase of 41%, effectively solving the topless problem. To verify the effectiveness of this solution, one half of a photomask was configured with a scheme lacking a phase-shifting layer and compensation pattern, while the other half was configured with the solution of this invention. Exposure of the same photoresist layer was performed. The area where the related technology was located exhibited a topless problem. See [link to relevant documentation]. Figure 14 The topless region was used in the solution, while the region where this solution was applied was the OK region. The thickness of the developed area was increased from 0.6756 μm in the topless region to 1.1009 μm, thus solving the topless problem.

[0112] See also, as an example of an implementation method. Figure 5 As shown, in the first direction, the phase-shifted region 11 is located at the boundary of the exposure region 23, and the distance between it and the boundary of the adjacent light-blocking pattern 21 is A:

[0113] A = (bce) / 2;

[0114] Where b is the distance between adjacent light-blocking patterns 21 in the first direction, c is the width of the transfer pattern corresponding to the exposure area 23 in the first direction, and e is the width of the light compensation pattern 22 in the first direction.

[0115] As an implementation method, in the first direction, the width e of the light compensation pattern 22 is 0.5-1.5 μm.

[0116] As an implementation method, the width e of the light compensation pattern 22 in the first direction is 1 μm.

[0117] It should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., used above to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise stated, "a plurality of" means two or more.

[0118] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A photomask template for fabricating a black matrix (BM), characterized in that, The device includes a photomask body, which comprises a transparent substrate, a phase-shifting layer, and a light-shielding layer stacked together. The transparent substrate is located between the phase-shifting layer and the light-shielding layer, or the transparent substrate is located on the side of the phase-shifting layer away from the light-shielding layer, or the transparent substrate is located on the side of the light-shielding layer away from the phase-shifting layer. The photomask body includes multiple light-blocking areas and an exposure area between the light-blocking areas. A light compensation pattern is disposed in the exposure area, and the light compensation pattern is located between two adjacent light-blocking patterns. The phase-shifting layer includes a non-phase-shifting region and a phase-shifting region surrounding the non-phase-shifting region. In a first direction, the orthographic projection of the phase-shifting regions on both sides of the non-phase-shifting region onto the transparent substrate covers the light-blocking pattern on adjacent sides of the light-compensating pattern.

2. The photomask template according to claim 1, characterized in that, The phase-shift region is used to cause a phase shift in a portion of the exposed light within the exposure region; The light shielding layer includes a plurality of light-blocking patterns and the light compensation pattern. Each light-blocking pattern is used to define the light-blocking area, and the area between the light-blocking patterns is used to define the exposure area. The plurality of light-blocking patterns are arranged in an array along intersecting first and second directions. In the first direction, the distance between adjacent light-blocking patterns is less than the distance between adjacent light-blocking patterns in the second direction; the light compensation pattern is located between adjacent light-blocking patterns in the first direction.

3. The photomask template according to claim 2, characterized in that, The orthogonal projection of the exposed region on the transparent substrate covers the orthogonal projection of the non-phase-shifted region on the transparent substrate; The orthogonal projection of the exposure area on the transparent substrate covers a portion of the orthogonal projection of the phase-shifting area on the transparent substrate; The orthogonal projection of the phase-shifting region on the transparent substrate overlaps the orthogonal projection of the light-blocking pattern on the transparent substrate.

4. The photomask template according to claim 2 or 3, characterized in that... In the first direction, the phase-shifted region is located at the boundary of the exposure region, and the distance between it and the boundary of the adjacent light-blocking pattern is A: A = (bce) / 2; Where b is the distance between adjacent light-blocking patterns in the first direction, c is the width of the transfer pattern corresponding to the exposure area in the first direction, and e is the width of the light compensation pattern in the first direction.

5. The photomask template according to claim 2, characterized in that, The orthographic projection of the light compensation pattern on the transparent substrate is located in the middle of the orthographic projection of the exposure area on the transparent substrate; the orthographic projection of the light compensation pattern on the light-blocking pattern falls within the light-blocking pattern.

6. The photomask template according to claim 2 or 3, characterized in that, The side of the light compensation pattern parallel to the second direction is shorter than the side of the light blocking pattern parallel to the second direction.

7. The photomask template according to claim 6, characterized in that, The distance between the side of the light compensation pattern parallel to the first direction and the side of the corresponding light blocking pattern parallel to the first direction in the second direction is 1-10 μm.

8. The photomask template according to claim 2, characterized in that, In the second direction, the length of the light compensation pattern is less than the length of the light blocking pattern, and in an orthographic projection perpendicular to the second direction, the light blocking pattern covers the light compensation pattern.

9. The photomask template according to claim 8, characterized in that, In the second direction, the distance between the apex corner of any end of the light-blocking pattern and the corresponding end of the light-compensating pattern is 1-10 μm; the apex corner is the angle closest to the corresponding end of the light-compensating pattern.

10. The photomask template according to claim 2, characterized in that, The light compensation pattern is a strip pattern extending in the second direction.

11. The photomask template according to claim 2, characterized in that, In the first direction, the width of the light compensation pattern is 0.5-1.5 μm.

12. The photomask template according to any one of claims 1-3, characterized in that, The phase-shifting layer is used to make the phase shift of a portion of the exposed light in the exposure area 180°±60°.

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