A method for manufacturing a mask plate and a mask plate

Abstract

The present disclosure provides a mask plate manufacturing method and a mask plate. The manufacturing method comprises the following steps: providing a stack structure, the stack structure comprising a transparent base material layer, a phase shift material layer and a light shielding material layer stacked; removing part of the transparent base material layer, part of the phase shift material layer and part of the light shielding material layer to transfer a first pattern to the transparent base material layer, the phase shift material layer and the light shielding material layer, obtaining a first intermediate body, the first pattern forming a groove in the transparent base material layer; performing a groove depth control process on the groove of the first intermediate body, obtaining a second intermediate body; removing part of the light shielding material layer of the second intermediate body to transfer a second pattern to the light shielding material layer, obtaining a third intermediate body; performing a height control process on the phase shift material layer of the third intermediate body, obtaining a mask plate. The manufacturing method of the present disclosure can timely rework and correct the mask plate with unqualified phase shift and transmittance, effectively ensuring product quality and production efficiency.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of electronic manufacturing technology, and in particular, to a mask plate manufacturing method and a mask plate. BACKGROUND

[0002] A mask plate, also known as a photomask or a photo mask, is a patterned template used in photolithography in microelectronic and integrated optoelectronic manufacturing, and has been widely used in various fields such as semiconductors, flat panel displays, micro-electro-mechanical systems, etc.

[0003] Phase shift mask (PSM) technology is a relatively common mask technology that can effectively improve the pattern contrast and resolution, but has the problem of low product quality and yield. SUMMARY

[0004] The following is a summary of the subject matter of the detailed description of the present disclosure. This summary is not intended to limit the scope of protection of the claims.

[0005] In a first aspect, the present disclosure provides a mask plate manufacturing method, comprising:

[0006] providing a stack structure, the stack structure comprising a transparent base material layer, a phase shift material layer and a light shielding material layer stacked together;

[0007] removing part of the transparent base material layer, part of the phase shift material layer and part of the light shielding material layer to transfer a first pattern to the transparent base material layer, the phase shift material layer and the light shielding material layer, to obtain a first intermediate body, the first pattern forming a groove in the transparent base material layer;

[0008] performing a groove depth control process on the groove of the first intermediate body to obtain a second intermediate body;

[0009] removing part of the light shielding material layer of the second intermediate body to transfer a second pattern to the light shielding material layer to obtain a third intermediate body;

[0010] performing a height control process on the phase shift material layer of the third intermediate body to obtain the mask plate.

[0011] In some embodiments, the performing a groove depth control process on the groove of the first intermediate body comprises:

[0012] detecting a groove depth of the groove;

[0013] if the groove depth does not meet a target depth size requirement, continuing to remove part of the transparent base material layer to change the groove depth of the groove until the groove depth of the groove meets the target depth size requirement.

[0014] In some embodiments, the detecting the groove depth of the groove comprises:

[0015] detecting a surface morphology of the first intermediate body by using an atomic force microscope;

[0016] determining the groove depth of the groove based on a result of the atomic force microscope.

[0017] In some embodiments, the continuing to remove part of the transparent base material layer to change the groove depth of the groove comprises:

[0018] etching the transparent base material layer to change the groove depth of the groove, taking the light-shielding material layer of the first intermediate body as a mask.

[0019] In some embodiments, the stack structure further comprises a first photoresist layer stacked on the light-shielding material layer;

[0020] The removing part of the transparent base material layer, part of the phase shift material layer and part of the light-shielding material layer comprises:

[0021] forming the first pattern on the first photoresist layer;

[0022] etching the transparent base material layer, the phase shift material layer and the light-shielding material layer, taking the first photoresist layer as a mask;

[0023] removing the first photoresist layer to obtain the first intermediate body.

[0024] In some embodiments, the height control process on the phase shift material layer of the third intermediate body comprises:

[0025] detecting a thickness of the phase shift material layer in the third intermediate body;

[0026] determining a target removal thickness of the phase shift material layer based on the thickness of the phase shift material layer in the third intermediate body and a target thickness;

[0027] removing the target removal thickness of the phase shift material layer.

[0028] In some embodiments, the detecting the thickness of the phase shift material layer in the third intermediate body comprises:

[0029] detecting a surface morphology of the third intermediate body by using an atomic force microscope;

[0030] determining the thickness of the phase shift material layer based on a result of the atomic force microscope.

[0031] In some embodiments, the removing the part of the light-shielding material layer of the second intermediate body comprises:

[0032] forming a second photoresist layer on the second intermediate body;

[0033] forming the second pattern on the second photoresist layer;

[0034] etching the light-shielding material layer with the second photoresist layer as a mask.

[0035] In some embodiments, the removing the target removal thickness of the phase shift material layer comprises:

[0036] simultaneously cleaning the second photoresist layer and the phase shift material layer to remove the second photoresist layer and the target removal thickness of the phase shift material layer.

[0037] In a second aspect, the present disclosure provides a mask plate, which is manufactured by the manufacturing method of the first aspect.

[0038] The manufacturing method of the mask plate provided by the present disclosure converts the control of the phase shift and the transmittance into the control of the structure size in the manufacturing process by performing the groove depth control process and the height control process on the intermediate body respectively, so that the unqualified structure can be reprocessed and corrected in time in the manufacturing process, which greatly reduces the number of waste products and effectively ensures the product quality and production efficiency of the mask plate.

[0039] Other aspects can become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating the embodiments of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the embodiments of the present disclosure. In the drawings:

[0041] Figure 1 A flow chart of the manufacturing method of the mask plate according to an exemplary embodiment is shown.

[0042] FIGS. 2(a)-(h) are schematic diagrams of the manufacturing method of the mask plate according to an exemplary embodiment.

[0043] Figure 3 FIG. 2(h) is an enlarged view of the area A.

[0044] Figure 4A flow chart of step S300 according to an exemplary embodiment is shown.

[0045] Figure 5 A flow chart of step S200 according to an exemplary embodiment is shown.

[0046] Figure 6 A flow chart of step S500 according to an exemplary embodiment is shown.

[0047] Figure 7 A flow chart of step S400 according to an exemplary embodiment is shown.

[0048] Figure 8 A flow chart of a method for manufacturing a mask plate according to another exemplary embodiment is shown.

[0049] Reference signs:

[0050] 11 - stacked structure; 12 - first intermediate body; 13 - second intermediate body; 14 - third intermediate body; 15 - mask plate;

[0051] 21 - first photoresist layer; 22 - light shielding material layer; 23 - phase shift material layer; 24 - transparent base material layer; 25 - second photoresist layer;

[0052] 220 - light shielding layer; 230 - phase shift layer; 240 - transparent base layer;

[0053] 31 - light transmission area; 310 - groove; 32 - phase shift area; 33 - light shielding area. DETAILED DESCRIPTION

[0054] In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only some but not all of the embodiments of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present disclosure. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict under the premise of no conflict.

[0055] Binary mask is the most commonly used mask plate form, mainly including a transparent substrate layer and an opaque light shielding layer, the light shielding layer is etched on the substrate layer to form a mask pattern, and the pattern information is transferred to the product substrate through exposure. However, when the design size reaches 0.18 μm or less, the pattern size on the traditional binary mask is reduced to a scale close to the wavelength of the light source, and the light at the edge of the pattern will be diffracted and expanded laterally. The small features that should be blocked by the light shielding layer will also be illuminated by the light from both sides, so that the projected pattern is no longer clear in light and dark. Through the phase shift mask technology, a phase shift layer is added in the binary mask, which can make the light waves passing through adjacent transparent regions have a phase difference of 180 degrees. In a certain area of the image plane, the two will interfere destructively, reducing the light intensity of the dark field and increasing the light intensity of the bright field, thereby significantly improving the contrast and resolution of the pattern.

[0056] For example, referring to FIG. 2(h), the mask plate 15 includes a light shielding layer 220, a phase shift layer 230 and a transparent substrate layer 240 arranged in layers. The mask plate 15 is usually formed by at least two etching processes, wherein the first etching process is performed along the first pattern to transfer the first pattern to the transparent substrate layer 240 to form the transparent region 31, and the second etching process is performed along the second pattern to transfer the second pattern to the phase shift layer 230 to form the phase shift region 32. The region where the light shielding layer 220 is located forms the light shielding region 33. The light rays located in the light shielding region 33 are blocked by the light shielding layer 220 and cannot enter the mask plate 15, while the light rays located in the transparent region 31 and the phase shift region 32 can enter the mask plate 15 through the transparent substrate layer 240 and the phase shift layer 230 respectively, so that the mask plate 15 can project a pattern along the outline of the second pattern.

[0057] Reference Figure 3 When the light rays enter the transparent region 31 and the phase shift region 32 respectively, the medium through which the light rays penetrate the mask plate 15 differs in structure and material, which can change the phase and transmittance of the light rays and also cause differences. When the phase difference of the light rays at the adjacent transparent region 31 and phase shift region 32 is 180 degrees, a better destructive interference effect can be obtained to significantly improve the contrast and resolution of the projected pattern of the mask plate 15. At the same time, the transmittance of the phase shift region 32 in the phase shift mask also has certain requirements, on the one hand to ensure that enough light rays can pass through the mask plate 15 and participate in the imaging process, and on the other hand to increase the light intensity difference between the dark field and the bright field by controlling the transmittance difference between the transparent region 31 and the phase shift region 32, further improving the contrast and resolution of the pattern. Therefore, in the phase shift mask technology, the phase shift degree and the transmittance can jointly determine the quality of the imaging, which are key parameters that have a key influence on the product quality of the mask plate and the imaging effect.

[0058] However, in the existing phase shift mask manufacturing process, the detection of the phase shift degree and the transmittance of the mask plate is usually performed after the manufacturing is completed, at which time the etching process has been finished, the mask plate lacks the structure layer that can be used as a mask (see Fig. 2 (h)), and the mask plate that fails to pass the detection cannot be reprocessed and corrected, thus resulting in low product quality and low qualification rate.

[0059] To solve the above problems, the inventors of the present application find that according to the wave optics principle, the phase shift degree of light wave passing through a medium depends on the optical path of the light wave propagating in the medium, and the optical path is equal to the product of the refractive index n of the medium and the thickness S. In addition, the transmittance of the light wave passing through the medium is related to the extinction coefficient k and the thickness S of the medium. Therefore, the control of the phase shift degree and the transmittance in the mask plate can be converted into the control of the thickness of the structure layer of the mask plate during the manufacturing of the mask plate.

[0060] Referring to Fig. 2 (h) and Figure 3 In the mask plate 15, the phase shift layer 230 is only provided at the phase shift area 32, and the thicknesses of the transparent base layer 240 at the transparent area 31 and the phase shift area 32 are also different, so that the phase shift degree and the transmittance of the light at the transparent area 31 and the phase shift area 32 are different. The thickness difference of the transparent base layer 240 at the transparent area 31 and the phase shift area 32 is the groove depth S1, and the thickness difference of the phase shift layer 230 is the target thickness S4. The phase shift degree is related to the groove depth S1 and the target thickness S4, and since the transparent base layer 240 is a transparent medium, the transmittance difference is related to the target thickness S4. Therefore, by designing the thicknesses of the phase shift layer 230 and the transparent base layer 240 and controlling the groove depth S1 and the target thickness S4 during the manufacturing, the light passing through the phase shift area 32 of the mask plate 15 can have a phase difference of 180 degrees relative to the transparent area 31, and the transmittance of the phase shift area 32 can be controlled to ensure that the phase shift degree and the transmittance of the mask plate 15 meet the requirements.

[0061] To solve the above problems, the embodiment of the present disclosure provides a mask plate manufacturing method, comprising the following steps: providing a stacked structure, the stacked structure comprising a transparent base material layer, a phase shift material layer and a light shielding material layer stacked; removing part of the transparent base material layer, part of the phase shift material layer and part of the light shielding material layer to transfer a first pattern to the transparent base material layer, the phase shift material layer and the light shielding material layer, to obtain a first intermediate body, the first pattern forming a groove in the transparent base material layer; performing a groove depth control process on the groove of the first intermediate body to obtain a second intermediate body; removing part of the light shielding material layer of the second intermediate body to transfer a second pattern to the light shielding material layer to obtain a third intermediate body; performing a height control process on the phase shift material layer of the third intermediate body to obtain a mask plate. By performing the groove depth control process and the height control process on the intermediate body respectively, the control of the phase shift and the transmittance is converted into the control of the structure size in the manufacturing process, so that the unqualified structure can be reprocessed and corrected in time in the manufacturing process, greatly reducing the number of waste products and effectively ensuring the product quality and production efficiency of the mask plate.

[0062] As shown in Figure 1 The embodiment provides a mask plate manufacturing method, specifically comprising the following steps:

[0063] Step S100: providing a stacked structure, the stacked structure comprising a transparent base material layer, a phase shift material layer and a light shielding material layer stacked.

[0064] As shown in FIG. 2(a), the stacked structure 11 is the manufacturing blank of the mask plate 15, the stacked structure 11 comprising a light shielding material layer 22, a phase shift material layer 23 and a transparent base material layer 24 stacked, the phase shift material layer 23 being located between the light shielding material layer 22 and the transparent base material layer 24. When manufacturing the stacked structure 11, the phase shift material layer 23 and the light shielding material layer 22 can be sequentially deposited on the transparent base material layer 24. The light shielding material layer 22 can be located above the phase shift material layer 23 to block the light from passing through the phase shift material layer 23 while protecting the phase shift material layer 23. Referring to FIG. 2(h), the light shielding material layer 22 in the stacked structure 11 is used to form a light shielding layer 220 of the mask plate 15, the phase shift material layer 23 is used to form a phase shift layer 230 of the mask plate 15, and the transparent base material layer 24 is used to form a transparent base layer 240 of the mask plate 15.

[0065] The light shielding material layer 22 is mainly composed of non-transparent material, and hard light shielding material such as chromium, silicon and iron oxide is usually used. These materials can effectively block light from passing through the specific area of the mask plate, especially the area that does not need to be exposed, to form bright and dark areas on the mask plate, thereby forming an accurate pattern profile. Among them, chromium is the most commonly used light shielding layer material due to its high mechanical strength and ability to form fine patterns. The phase shift material layer 23 is used to adjust the phase shift and transmittance simultaneously by its partial light transmittance, thereby improving the resolution and contrast of the image. Typical materials include molybdenum silicide (MoSi) and the like. The transparent base material layer 24 can typically be made of synthetic quartz glass material. Compared with ordinary glass, quartz has the advantages of high light transmittance (especially in the deep ultraviolet waveband), small thermal expansion coefficient, stable optical properties, and moderate refractive index n, which is beneficial to precise control of the phase of light waves. It is an ideal base material for phase shift mask technology. Of course, the light shielding material layer 22, the phase shift material layer 23 and the transparent base material layer 24 can also be made of other materials, which are not limited here.

[0066] Step S200: removing part of the transparent base material layer, part of the phase shift material layer and part of the light shielding material layer to transfer the first pattern to the transparent base material layer, the phase shift material layer and the light shielding material layer, to obtain a first intermediate body, and the first pattern forms a groove in the transparent base material layer.

[0067] As shown in Figures 2(a) to 2(c) The light shielding material layer 22, the phase shift material layer 23 and the transparent base material layer 24 can be etched along the outline area of the first pattern in sequence, or other removal means can be used, so that the first pattern penetrates the light shielding material layer 22 and the phase shift material layer 23, and forms a groove 310 on the transparent base material layer 24 to obtain a first intermediate body 12. The groove 310 forms a light transmission area 31, and the part between the two adjacent light transmission areas 31 which is not etched by the first pattern and protrudes relative to the groove 310 forms a phase shift area 32.

[0068] Step S300: performing a groove depth control process on the groove of the first intermediate body to obtain a second intermediate body.

[0069] As shown in Figures 2(c) to 2(d)As shown, after step S200, a light-transmitting area 31 is formed on the transparent substrate material layer 24 of the first intermediate 12. The fabrication operations following the completion of the groove depth control process will not affect the groove depth S1 or related detection results. This point can be considered the control point for the groove depth S1, and the groove depth S1 is detected and corrected by executing the groove depth control process. When the groove depth S1 does not match the preset depth, the first intermediate 12 can be etched again in a timely manner. After the groove depth control process is completed, a second intermediate 13 with a groove depth S1 matching the preset depth is obtained. It should be noted that the groove depth control process can be completed before the light-shielding material layer 22 is removed to ensure that a structural layer capable of serving as a mask exists on the first intermediate during the groove depth control process. This also prevents the thickness S2 of the phase shift layer 230 from changing due to etching of the phase shift material layer 23 on the phase shift region 32, thus affecting the subsequent height control process. For example, the groove depth control process can be performed at step 2(c) using the first photoresist layer 21 (described in detail below) as a mask, or at step 2(f) using the light-shielding material layer 22 as a mask, without any limitation.

[0070] Step S400: Remove part of the light-shielding material layer of the second intermediate to transfer the second pattern to the light-shielding material layer, thereby obtaining the third intermediate.

[0071] like Figures 2(d) to 2(g) As shown, the light-shielding material layer 22 can be etched along the contour region of the second pattern based on the second intermediate 13, or other removal methods can be used. The contour region of the second pattern includes the projection region of the light-transmitting region 31 and the phase-shifting region 32 formed by the first pattern, so that the light-shielding material layer 22 in the phase-shifting region 32 is removed to obtain the third intermediate 14. In the phase-shifting region 32 of the third intermediate 14, light can directly enter the phase-shifting material layer 23 without being blocked by the light-shielding material layer 22.

[0072] Step S500: Perform a height control process on the phase shift material layer of the third intermediate to obtain a mask.

[0073] like Figures 2(g) to 2(h) as well as Figure 3 As shown, after step S400, a third intermediate 14 is obtained. The phase shift material layer 23 on the phase shift region 32 is exposed on the upper surface of the third intermediate 14. Part of the phase shift material layer 23 on the phase shift region 32 can be removed. The removal method can be, for example, cleaning. At this time, it can be regarded as the control point of the target thickness S4. The manufacturing parameters of the phase shift material layer 23 are determined by executing the height control process to ensure that the mask 15 with the target thickness S4 can be obtained after removing part of the phase shift material layer 23.

[0074] In this embodiment, reference Figures 2(a) to 2(h)and Figure 3 By performing the groove depth control process on the first intermediate body 12 at the control point of the groove depth S1 and performing the height control process on the third intermediate body 14 at the control point of the target thickness S4, the control of the phase shift degree and the transmittance of the mask plate 15 is converted into the control of the groove depth S1 and the target thickness S4, so that whether the mask plate 15 is qualified can be judged by the groove depth S1 and the target thickness S4 during the manufacturing process, and the mask plate 15 can be reprocessed and corrected in time when it is unqualified, thereby greatly reducing the number of waste products and effectively ensuring the product quality and production efficiency of the mask plate 15.

[0075] In an embodiment, as shown in Figure 4 , the groove depth control process specifically includes the following steps:

[0076] Step S310: detecting the groove depth of the groove.

[0077] Step S320: if the groove depth does not meet the target depth size requirement, continue to remove part of the transparent substrate material layer to change the groove depth of the groove until the groove depth of the groove meets the target depth size requirement.

[0078] As described above, referring to Figure 3 , the phase shift degree is related to both the groove depth S1 and the target thickness S4, and the transmittance is related to the groove depth S1, so the target depth size of the groove depth S1 can be determined according to the required phase shift degree and transmittance.

[0079] In an example, the target depth size of the groove depth S1 can be directly calculated mathematically according to the operation formula of the groove depth S1, the refractive index n1 of the transparent substrate material layer 24, the target thickness S4, the refractive index n2 of the phase shift material layer 23, and the refractive index n3 of air and the phase shift degree. In another example, when individual parameters are inconvenient to obtain, for example, it is difficult to obtain the accurate value of n2, a mathematical model can also be established in advance to obtain an empirical formula for easy calculation (detailed below).

[0080] In an embodiment, step S310 specifically includes the following steps:

[0081] Step S311: detecting the surface morphology of the first intermediate body by using an atomic force microscope.

[0082] Step S312: determining the groove depth of the groove based on the detection result of the atomic force microscope.

[0083] Atomic force microscopy (AFM) can provide realistic three-dimensional surface images without requiring special sample preparation. It can directly observe surface morphology and physical properties at the nanometer level and avoids irreversible damage to the first intermediate 12. Referring to Figure 2(c), by inspecting the upper surface of the first intermediate 12 and analyzing the inspection results, the surface morphology of the first intermediate 12 can be obtained, thereby determining the groove depth S1 at the light-transmitting area 31.

[0084] In one embodiment, when the groove depth S1 does not meet the target depth requirement, step S320 specifically includes the following steps until the target depth requirement is met:

[0085] Step S321: Using the light-shielding material layer of the first intermediate as a mask, etch the transparent substrate material layer to change the groove depth of the groove 310.

[0086] When the groove depth S1 is found to be insufficient, at least a light-shielding material layer 22 still exists above the phase-shifting material layer 23 of the first intermediate body 12. Therefore, the light-shielding material layer 22 can be used as a mask to re-etch the transparent substrate material layer 24 along the contour area of ​​the first pattern to increase the groove depth S1. This allows for timely correction of the first intermediate body 12 whose dimensions do not meet the requirements, providing a large margin of error. The etching depth for each step can be determined according to the actual situation to balance manufacturing efficiency and accuracy.

[0087] In one embodiment, as shown in FIG2(a), the stacked structure 11 further includes a first photoresist layer 21 stacked on the light-shielding material layer 22. The first photoresist layer 21 and the phase-shifting material layer 23 are respectively located on opposite sides of the light-shielding material layer 22. The first photoresist layer 21 is formed by photoresist coated on the light-shielding material layer 22. Photoresist is a photosensitive material that undergoes chemical changes under ultraviolet light or other specific light irradiation. It is divided into positive photoresist and negative photoresist. Positive photoresist is soluble in developer after exposure, while negative photoresist is soluble in developer before exposure. Therefore, depending on the type of photoresist used in the first photoresist layer 21, a specific area of ​​the photoresist layer can be exposed to record a mask pattern.

[0088] like Figure 5 As shown, step S200 specifically includes the following steps:

[0089] Step S210: Form a first pattern on the first photoresist layer.

[0090] Step S220: Using the first photoresist layer as a mask, etch the transparent substrate material layer, the phase-shifting material layer, and the light-shielding material layer.

[0091] Step S230: Remove the first photoresist layer to obtain the first intermediate.

[0092] In one example, referring to Figure 2(b), a patterning machine can be used to pattern and expose the first photoresist layer 21. Specifically, the first pattern is first input into the patterning machine, which then outputs specific light (e.g., a laser) to irradiate the first photoresist layer 21 according to the first pattern for point exposure, thereby forming the desired first pattern. Subsequently, the first photoresist layer 21 with the first pattern can be used as a mask for etching to transfer the first pattern to the light-shielding material layer 22, the phase-shifting material layer 23, and the transparent substrate material layer 24.

[0093] In one example (not shown in the attached diagram), the first photoresist layer 21 can be removed after the first pattern is transferred to obtain the first intermediate 12. In another example, refer to... Figures 2(c) to 2(d) Alternatively, the first photoresist layer 21 can be left unremoved so that during the groove depth control process in step S300, the first photoresist layer 21 can be used as a mask for re-etching until the groove depth control process is completed, at which point the first photoresist layer 21 can be removed.

[0094] In one embodiment, such as Figure 6 As shown, the height control process specifically includes the following steps:

[0095] Step S510: Detect the thickness of the phase-shifting material layer in the third intermediate.

[0096] Step S520: Determine the target removal thickness of the phase shifting material layer based on the thickness of the phase shifting material layer in the third intermediate and the target thickness.

[0097] Step S530: Remove the phase-shifted material layer of the target removal thickness.

[0098] like Figure 3 As shown, in the phase shift layer 230, the thickness S2 is equal to the sum of the target removal thickness S3 and the target thickness S4. After determining the thickness S2 and the target thickness S4 respectively, the target removal thickness S3 can be determined, and then an appropriate cleaning intensity can be selected to ensure that the target thickness S4 remaining after cleaning meets the requirements.

[0099] Referring to the aforementioned groove depth control process, and Figure 3 As shown, the target thickness S4 can be determined based on the required transmittance. In one example, the target thickness S4 can be determined directly by mathematical calculation based on the reflectivity R of each medium interface, the extinction coefficient k of the phase shift layer 230, and the formula for calculating the target thickness S4 and transmittance. In another example, when certain parameters are inconvenient to obtain, such as when it is difficult to obtain an accurate value for k, a mathematical model can be established in advance to obtain an empirical formula for calculation.

[0100] In an example, empirical coefficients can be preset to establish the mathematical model, and an empirical formula is obtained according to the empirical coefficients, so as to determine the target depth size of the groove depth S1 and the target thickness S4 according to the required phase shift degree and the transmittance. For example, since the phase shift degree is in a proportional relationship with the medium thickness, and the transmittance is in an exponential relationship with the medium thickness with a natural constant e as the base, the following empirical formula can be preset:

[0101] First phase shift degree = a1 * S1

[0102] Second phase shift degree = a2 * S1 + a3 * S4

[0103]

[0104] In the formula, the first phase shift degree is the phase shift degree of the light before the phase shift material layer 23 is cleaned (referring to FIG. 2(g)), at this time, the phase shift degree of the light is only affected by the groove depth S1; the second phase shift degree is the phase shift degree of the light after the phase shift material layer 23 is cleaned (referring to FIG. 2(h)), that is, the phase shift degree of the mask plate 15, at this time, both the groove depth S1 and the target thickness S4 can affect the phase shift degree of the light; a1, a2, a3, a4 and a5 are all preset empirical coefficients.

[0105] Another stack structure 11 with the same structure and material is taken, and the stack structure 11 is manufactured as shown in FIG. 2(c). A plurality of grooves 310 with different depths are etched at the control point of the groove depth S1 as shown in FIG. 2(c), and the phase shift degree of the light is measured at the first measurement point to obtain the first phase shift degree corresponding to the plurality of groove depths S1 respectively, so as to determine the empirical coefficient a1. The first measurement point can be located at the step as shown in FIG. 2(g), at this time, the light shielding material layer 22 on the phase shift area 32 has been removed, so as to facilitate the light to pass through for measurement. Figures 2(a) to 2(h) The phase shift material layer 23 on the phase shift area 32 is cleaned at different intensities at the control point of the target thickness S4 as shown in FIG. 2(h) to obtain a plurality of phase shift material layers 23 with different target thicknesses S4 on the plurality of phase shift areas 32. The phase shift degree and the transmittance of the light are measured at the second measurement point (after the step as shown in FIG. 2(h)) to obtain the second phase shift degree and the transmittance corresponding to the plurality of different groove depths S1 and the target thicknesses S4 respectively, so as to determine the empirical coefficients a2, a3, a4 and a5.

[0106] In the formula, the first phase shift degree is the phase shift degree of the light before the phase shift material layer 23 is cleaned (referring to FIG. 2(g)), at this time, the phase shift degree of the light is only affected by the groove depth S1; the second phase shift degree is the phase shift degree of the light after the phase shift material layer 23 is cleaned (referring to FIG. 2(h)), that is, the phase shift degree of the mask plate 15, at this time, both the groove depth S1 and the target thickness S4 can affect the phase shift degree of the light; a1, a2, a3, a4 and a5 are all preset empirical coefficients.

[0107]

[0108] ​After determining the empirical coefficients, the empirical formula can be obtained, and the target depth dimension S1 and target thickness S4 of the groove depth S1 at the corresponding control point can be determined by the required phase shift and transmittance. This allows the phase shift and transmittance of the product to be judged to meet the requirements by directly measuring and comparing the structural dimensions of the intermediate body during the fabrication of the mask 15.

[0109] In one embodiment, step S510 specifically includes the following steps:

[0110] Step S511: Detect the surface morphology of the third intermediate using an atomic force microscope;

[0111] Step S512: Determine the thickness of the phase-shifting material layer based on the detection results of atomic force microscopy.

[0112] As mentioned earlier, atomic force microscopy can acquire the surface morphology of a sample, which can then be used to determine the thickness S2 of the phase-shifting material layer 23 in the third intermediate 14 based on the height of the detected phase-shifting region 32 and the groove depth S1. The principle behind this is not elaborated here. Using the fabrication method provided in this embodiment, precise control of the phase shift and transmittance of the mask 15 can be achieved simply by detecting the groove depth S1 and thickness S2 at two corresponding control points. This significantly reduces the difficulty of process control for the mask 15 and improves the fabrication efficiency and product quality of the mask 15.

[0113] In one embodiment, such as Figure 7 As shown, step S400 specifically includes the following steps:

[0114] Step S410: Form a second photoresist layer on the second intermediate.

[0115] Step S420: Form a second pattern on the second photoresist layer.

[0116] Step S430: Using the second photoresist layer as a mask, etch the light-shielding material layer.

[0117] like Figures 2(e) to 2(g) As shown, in order for light to pass through the phase shift region 32, the light-shielding material layer 22 on the phase shift region 32 of the second intermediate 13 needs to be removed. The removal method can be to re-coat photoresist onto the second intermediate 13 to form a second photoresist layer 25 (refer to FIG. 2(e)), and use the second photoresist layer 25 with the second pattern as a mask (refer to FIG. 2(f)) for etching, transferring the second pattern to the light-shielding material layer 22 (refer to FIG. 2(g)), thereby obtaining the third intermediate 14. The fabrication of the second photoresist layer 25 can be referenced to the first photoresist layer 21, and will not be elaborated here.

[0118] Referring to Figure 2(g), after the light-shielding material layer 22 is etched, the second photoresist layer 25 may still exist on the third intermediate 14. In one embodiment, step S530 specifically includes the following steps:

[0119] Step S531: Simultaneously clean the second photoresist layer and the phase shift material layer to remove the second photoresist layer and the phase shift material layer of the target removal thickness.

[0120] like Figures 2(g) to 2(h) As shown, by cleaning, the second photoresist layer 25 is removed at the same time as the phase shift material layer 23 with a target removal thickness S3, resulting in a photomask 15 that does not contain photoresist and meets the quality requirements.

[0121] An exemplary embodiment of this disclosure provides a method for creating a mask template, such as... Figure 8 and combined Figures 2(a) to 2(h) As shown, the manufacturing method includes the following steps:

[0122] Step S10: Provide a stacked structure, the stacked structure including a first photoresist layer, a transparent substrate material layer, a phase shifting material layer and a light-shielding material layer stacked together.

[0123] Step S20: A first pattern is formed on the first photoresist layer of the stacked structure. Using the first photoresist layer as a mask, a light-shielding material layer, a phase-shifting material layer, and a transparent substrate material layer are etched until the first pattern forms a groove on the transparent substrate material layer to obtain a first intermediate.

[0124] Step S30: Perform a groove depth control process on the groove of the first intermediate. During the groove depth control process, use an atomic force microscope to detect the surface morphology of the first intermediate to determine the groove depth S1. When the groove depth S1 does not meet the target depth size, use the first photoresist layer or light-shielding material layer as a mask to etch the transparent substrate material layer again until the groove depth S1 meets the target depth size, and obtain the second intermediate.

[0125] Step S40: A second photoresist layer is formed on the second intermediate and a second pattern is formed on the second photoresist layer. The light-shielding material layer is etched away using the second photoresist layer as a mask to obtain the third intermediate.

[0126] Step S50: Perform a height control process on the phase shift material layer of the third intermediate. During the height control process, use an atomic force microscope to detect the surface morphology of the third intermediate to determine the thickness S2 of the phase shift material layer. Determine the target removal thickness S3 through the target thickness S4 and set the corresponding cleaning parameters. Clean the second photoresist layer and the phase shift material layer with the target removal thickness S3 on the third intermediate to obtain the photomask.

[0127] The specific operation and principle of the embodiment can refer to the foregoing embodiments, which will not be repeated here. In the manufacturing method in the embodiment, the control of the phase shift degree and the transmittance is converted into the control of the structure size in the manufacturing process by performing the groove depth control process on the first intermediate body and performing the height control process on the third intermediate body. The phase shift degree and the transmittance of the mask plate 15 can be precisely controlled only by detecting the groove depth S1 and the thickness S2 at two corresponding control points, which greatly reduces the process control difficulty of the mask plate 15 and improves the manufacturing efficiency and product quality of the mask plate 15. Meanwhile, when the groove depth S1 or the thickness S2 is detected to be not qualified, the unqualified structure can be reprocessed and corrected in the manufacturing process in time, which avoids the defect that the phase shift degree and the transmittance cannot be detected until the manufacturing is completed in the traditional manufacturing method and the unqualified product cannot be adjusted and corrected, greatly reduces the number of waste products, and effectively guarantees the product quality and production efficiency of the mask plate.

[0128] As shown in FIG. 2(g), the embodiment provides a mask plate 15, which can be manufactured by the manufacturing method in any of the foregoing embodiments. The mask plate 15 includes an opaque layer 220, a phase shift layer 230, and a transparent substrate layer 240. The mask plate 15 is formed with alternating light transmission regions 31 and phase shift regions 32 through etching of the first pattern and the second pattern, and 180-degree phase difference can be generated when light passes through the mask plate 15 through the light transmission regions 31 and the phase shift regions 32, respectively, to obtain a clear-edged pattern. Meanwhile, the light transmission region of the mask plate 15 also has high transmittance, which can ensure that enough light can pass through and participate in the imaging process.

[0129] The mask plate 15 provided by the embodiment realizes precise control of the phase shift degree and the transmittance by controlling the structure size of the phase shift material layer 23 and the transparent substrate material layer 24 of the intermediate body in the manufacturing process, which can better meet the requirements of the mask plate product on the phase shift degree and the transmittance, and the manufacturing method is simple and efficient, has the advantages of high product quality and fast production efficiency, and can provide reliable protection for subsequent electronic manufacturing and processing.

[0130] The embodiments or implementations in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the embodiments can be mutually referred to.

[0131] In the description of the specification, the description of the terms “embodiment”, “exemplary embodiment”, “some implementations”, “illustrative implementation”, “example” and the like means that the specific features, structures, materials or characteristics described in combination with the implementation or example are included in at least one implementation or example of the disclosure.

[0132] In this specification, the illustrative expressions of the terms used do not necessarily refer to the same implementation or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more implementations or examples.

[0133] In the description of this disclosure, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this disclosure 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. Therefore, they should not be construed as limitations on this disclosure.

[0134] It is understood that the terms "first," "second," etc., as used in this disclosure may be used to describe various structures, but these structures are not limited by these terms. These terms are only used to distinguish one structure from another.

[0135] In one or more accompanying drawings, the same elements are represented by similar reference numerals. For clarity, many parts in the drawings are not drawn to scale. Furthermore, certain well-known parts may not be shown. For simplicity, a structure obtained after several steps may be depicted in a single drawing. Many specific details of this disclosure, such as the structure, materials, dimensions, processing methods, and techniques of the devices, are described below to provide a clearer understanding of the disclosure. However, as those skilled in the art will understand, this disclosure may be implemented without adhering to these specific details.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A method for manufacturing a mask template, characterized in that, The manufacturing method includes: A stacked structure is provided, the stacked structure comprising a transparent substrate material layer, a phase-shifting material layer and a light-shielding material layer stacked together; A portion of the transparent substrate material layer, a portion of the phase-shifting material layer, and a portion of the light-shielding material layer are removed to transfer a first pattern to the transparent substrate material layer, the phase-shifting material layer, and the light-shielding material layer, thereby obtaining a first intermediate body, wherein the first pattern forms a groove in the transparent substrate material layer; A groove depth control process is performed on the groove of the first intermediate to obtain a second intermediate; A portion of the light-shielding material layer of the second intermediate is removed to transfer the second pattern to the light-shielding material layer, resulting in a third intermediate; The mask is obtained by performing a height control process on the phase-shifting material layer of the third intermediate. The process of performing groove depth control on the groove of the first intermediate includes: Detect the groove depth; If the groove depth does not meet the target depth requirement, continue to remove part of the transparent base material layer to change the groove depth until the groove depth meets the target depth requirement; The process of height control of the phase-shifting material layer of the third intermediate includes: Detect the thickness of the phase-shifting material layer in the third intermediate; Based on the thickness and target thickness of the phase-shifting material layer in the third intermediate, the target removal thickness of the phase-shifting material layer is determined; Remove the phase-shifting material layer of the target removal thickness.

2. The method for manufacturing a mask template according to claim 1, characterized in that, The detection of the groove depth includes: The surface morphology of the first intermediate was examined using atomic force microscopy. Based on the detection results of the atomic force microscope, the groove depth is determined.

3. The method for manufacturing a mask template according to claim 1, characterized in that, The step of further removing a portion of the transparent substrate material layer to change the groove depth includes: Using the light-shielding material layer of the first intermediate as a mask, the transparent substrate material layer is etched to change the groove depth.

4. The method for manufacturing a mask template according to any one of claims 1 to 3, characterized in that, The stacked structure further includes a first photoresist layer stacked on the light-shielding material layer; The removal of a portion of the transparent substrate material layer, a portion of the phase-shifting material layer, and a portion of the light-shielding material layer includes: The first pattern is formed on the first photoresist layer; Using the first photoresist layer as a mask, the transparent substrate material layer, the phase-shifting material layer, and the light-shielding material layer are etched. Remove the first photoresist layer to obtain the first intermediate.

5. The method for manufacturing a mask template according to claim 1, characterized in that, The detection of the thickness of the phase-shifting material layer in the third intermediate includes: The surface morphology of the third intermediate was examined using atomic force microscopy. The thickness of the phase-shifting material layer is determined based on the detection results of the atomic force microscope.

6. The method for manufacturing a mask template according to claim 1, characterized in that, The removal of a portion of the light-shielding material layer from the second intermediate includes: A second photoresist layer is formed on the second intermediate; The second pattern is formed on the second photoresist layer; Using the second photoresist layer as a mask, the light-shielding material layer is etched.

7. The method for manufacturing a mask template according to claim 6, characterized in that, The removal of the phase-shifting material layer with the target removal thickness includes: Simultaneously clean the second photoresist layer and the phase-shifting material layer to remove the second photoresist layer and the phase-shifting material layer to the target removal thickness.

8. A photomask, characterized in that, The mask template is manufactured using the manufacturing method described in any one of claims 1 to 7.

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