Photomask protection assembly, pressure-sensitive adhesive used by photomask protection assembly and preparation method of pressure-sensitive adhesive

Abstract

The invention relates to a photomask protection assembly, a pressure-sensitive adhesive used by the photomask protection assembly and a preparation method, the pressure-sensitive adhesive comprises a styrene block copolymer thermoplastic elastomer, the loss factor of the pressure-sensitive adhesive at 20 DEG C is 0.2-0.4, and the peak temperature of the loss factor is-30 DEG C to-10 DEG C. The viscoelasticity of the pressure-sensitive adhesive is precisely regulated and controlled, so that the pressure-sensitive adhesive can keep stable performance for a long time under a light-heat coupling working condition, colloid migration is effectively inhibited, and the adhesive residue risk during replacement of a protection assembly is reduced.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a photomask protection component, the pressure-sensitive adhesive used therein, and a preparation method thereof. Background Technology

[0002] Photomasks are key components in micro-nano manufacturing and semiconductor photolithography processes. The integrity and cleanliness of their surface patterns directly determine the accuracy of photolithography imaging and product yield. To prevent damage from dust, scratches, or other physical and chemical substances during transportation, storage, and use, a protective film is typically applied to the non-circuit patterned surface of the photomask. This protective film is usually fixed to the photomask surface by an aluminum frame, and pressure-sensitive adhesive is used to bond the photomask to the aluminum frame.

[0003] However, during actual operation, the high-intensity light exposure of lithography machines leads to a continuous increase in ambient temperature, creating harsh photo-thermal coupling conditions. Under these conditions, pressure-sensitive adhesives are prone to performance degradation due to photo-oxidative degradation and thermal aging of the polymer molecular chains. On one hand, the cohesive strength of the degraded pressure-sensitive adhesive decreases, and under long-term stress and heat, irreversible creep and flow may occur, causing the adhesive to migrate from the bonding interface between the aluminum frame and the photomask to the functional area of ​​the photomask. This migration becomes a contaminant adhering to the photomask surface. On the other hand, when the entire protective component needs to be replaced due to maintenance, cleaning, or the end of its lifespan, the degraded pressure-sensitive adhesive may not be able to maintain its complete cohesive strength, instead experiencing cohesive failure at the interface between the adhesive layer and the photomask. This results in a portion of the pressure-sensitive adhesive layer, which should remain intact on the aluminum frame, remaining on the photomask surface.

[0004] Therefore, regardless of which of the above situations occurs, the photomask surface will eventually become contaminated, which will have an adverse effect on the quality of photolithography imaging and ultimately lead to a decrease in product yield. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this application is to provide a photomask protection component, the pressure-sensitive adhesive used therein, and its preparation method. By precisely controlling the viscoelasticity of the pressure-sensitive adhesive, the adhesive can maintain long-term performance stability under photo-thermal coupling conditions, thereby effectively inhibiting adhesive migration and reducing the risk of residual adhesive when replacing the protection component.

[0006] To achieve the above objectives, the present application provides the following technical solution: a pressure-sensitive adhesive for a photomask protection component, wherein the pressure-sensitive adhesive comprises a styrene block copolymer thermoplastic elastomer, the pressure-sensitive adhesive has a loss factor of 0.19 to 0.35 at 20°C, and the peak temperature of the loss factor is -30°C to -10°C.

[0007] Compared with acrylic pressure-sensitive adhesives, pressure-sensitive adhesives prepared using styrene block copolymer thermoplastic elastomers such as SEBS, SBS, and SEPS have superior thermal stability and weather resistance, as well as stronger high-temperature resistance and UV resistance, making them more suitable for the photo-thermal coupling conditions inside lithography machines.

[0008] Furthermore, this type of pressure-sensitive adhesive requires no solvent or curing / crosslinking during preparation, thus avoiding bubble problems and solvent residue risks caused by solvent evaporation. In photolithography processes where environmental cleanliness is extremely important, increased temperature leading to the evaporation of residual solvents could affect UV light transmittance and interfere with the photolithography process. Therefore, the pressure-sensitive adhesive provided in this application offers advantages in terms of reliability and environmental adaptability.

[0009] Furthermore, the loss factor is the ratio of loss modulus to storage modulus. Research has shown that if the loss factor of the pressure-sensitive adhesive (PSA) at 20°C is less than 0.19, the PSA will be too elastic but lack sufficient adhesion. During initial bonding at room temperature, it will be difficult to fully wet and bond the photomask, posing a risk of poor initial adhesion. Consequently, during use, factors such as vibration or stress relaxation may cause displacement or even detachment. Moreover, excessive elasticity during use can lead to stress transmission to the photomask, causing deformation and resulting in uneven lithographic patterns. If the loss factor is greater than 0.35, the PSA will be too viscous and lack elastic recovery. In this case, its cohesive force is relatively weak. Under long-term stress and heat, the adhesive is prone to irreversible creep and flow, migrating from the bonding interface to the functional areas of the photomask, causing contamination. Simultaneously, low cohesive force also makes the adhesive layer prone to cohesive failure during maintenance and replacement, resulting in some adhesive residue remaining on the photomask surface.

[0010] Therefore, this application precisely controls the loss factor of the pressure-sensitive adhesive at 20°C within the range of 0.19 to 0.35, which ensures that the pressure-sensitive adhesive has the best balance between initial adhesion performance and cohesive strength under normal operating temperature. This balance is the primary condition for resisting performance degradation under light-heat coupling conditions, effectively inhibiting adhesive migration, and reducing the risk of residual adhesive when replacing protective components.

[0011] Furthermore, the peak temperature of the loss factor corresponds to the glass transition region where polymer chain segments are most active. If the peak temperature of the loss factor is greater than -10℃, its glass transition region is too close to or even enters the ambient temperature window of the photolithography process. This will not only cause the pressure-sensitive adhesive to have excessively high initial tack and poor operability at room temperature, but more importantly, when heated by light, the colloid will be in a state of high viscosity dissipation and photochemical activity for a long time, which will accelerate the aging of the material rapidly, leading to rapid degradation or cross-linking of molecular chains, performance deterioration, and a high risk of residual adhesive. Conversely, if the peak temperature of the loss factor is below -30℃, although it is far from the photolithography working temperature range, it will cause the polymer chain segments to move too freely, resulting in low cohesion of the material at room temperature and reduced morphological retention at high temperatures. It will also be difficult to resist heat-induced colloidal flow, thereby increasing the risk of migration during long-term use or residue during replacement.

[0012] Therefore, this application controls the peak temperature of the loss factor within the range of -30℃ to -10℃, effectively avoiding the room temperature and high temperature operating environments involved in the photolithography process in its sensitive glass transition region. This significantly suppresses intense photochemical reactions and viscous flow phenomena under long-term photo-thermal coupling conditions, thereby significantly improving its resistance to photoaging and long-term thermal stability, ensuring interface integrity and functional reliability throughout its entire lifespan. Simultaneously, the absence of room temperature and high temperature operating environments allows the loss factor curve to drop rapidly before reaching room temperature, thus maintaining a relatively constant loss factor at both room temperature and high temperatures. This ensures a constant viscoelastic state during use, further minimizing adhesive residue.

[0013] Based on this, this application, by synergistically controlling the loss factor and peak temperature of the pressure-sensitive adhesive at 20°C, can work together from two dimensions: static viscoelastic balance and dynamic environmental stability. This ensures that the pressure-sensitive adhesive can maintain stable performance for a long time under light-heat coupling conditions, thereby simultaneously suppressing the problems of adhesive migration and residual adhesive during replacement. In particular, it can also avoid the phenomenon of residual adhesive when used at high temperatures for a long time.

[0014] Furthermore, the peak value of the loss factor is A, where 1 < A < 1.5. At this point, the pressure-sensitive adhesive (PSA) has a relatively narrow glass transition region, enabling a more rapid and complete transition from the glassy state to the elastic state. This characteristic ensures that the PSA remains on a purer and more stable elastic plateau within the actual photolithography temperature range. In this state, the polymer chain movement is neither too restricted nor too free, thus maintaining a highly consistent viscoelastic response over long-term use. This not only helps maintain a precise balance between initial bond strength and cohesion, avoiding performance drift caused by temperature fluctuations, but also significantly improves the PSA's tolerance to photo-thermal coupling conditions. During periodic photothermal heating, the PSA is less prone to drastic changes in its viscoelastic state or accelerated aging due to repeated entry into or approach to the transition region. Therefore, the performance stability of the PSA can be further enhanced from a kinetic perspective, thereby more effectively suppressing adhesive migration and reducing the risk of residual adhesive during replacement.

[0015] In photolithography, the ambient temperature is typically maintained at around 20°C. However, during the process, due to the continuous exposure of high-intensity light, the photomask and its bonding interface experience a significant temperature rise due to photothermal effects, with local temperatures potentially reaching approximately 80°C. Therefore, by further controlling the loss factor difference to below 0.13 within the 20°C–80°C range, the viscoelastic properties of the pressure-sensitive adhesive can be maintained stably within this temperature range. This ensures consistent bonding strength and stress dissipation capability between the photomask and the protective component under different operating conditions. This stable performance effectively avoids problems such as interface stress concentration, accelerated adhesive creep, or abnormal changes in adhesive force caused by temperature fluctuations, thereby suppressing the risks of adhesive migration and thermally induced delamination, and providing a reliable material-level guarantee for the long-term stability of the photolithography process.

[0016] Furthermore, within the temperature range of 20℃ to 80℃, if the difference between the maximum and minimum storage modulus of the pressure-sensitive adhesive is too large, its elastic recovery and shape retention capabilities may become overly sensitive to temperature changes. Microscopically, the rigidity of the polymer network changes drastically with increasing temperature. This leads to a decrease in the morphological stability of the pressure-sensitive adhesive in the high-temperature range. Under long-term photo-thermal coupling, the adhesive is more prone to permanent deformation and structural relaxation, thereby reducing its long-term adhesion to the protective film and affecting the uniformity of interfacial stress distribution.

[0017] Therefore, this application controls the difference between the maximum and minimum values ​​of the energy storage modulus to below 2.5 MPa, ensuring that the elastic behavior of the pressure-sensitive adhesive remains stable throughout the entire operating temperature range. Thus, even under extreme photothermal conditions approaching 80°C, the pressure-sensitive adhesive can maintain effective shape retention and structural integrity, significantly improving its bonding reliability over a wide temperature range. Furthermore, this can be combined with the regulation of the loss factor and its peak temperature to optimize multiple dimensions, including viscoelastic balance, temperature sensitivity, viscous stability, and elastic stability. This helps improve the long-term stability of the interfacial bonding state of the pressure-sensitive adhesive under photothermal coupling conditions, fundamentally suppressing the problems of adhesive migration and residual adhesive replacement caused by performance degradation.

[0018] Furthermore, the pressure-sensitive adhesive has a storage modulus of 1 MPa to 3.1 MPa at 20°C, ensuring sufficient rigidity to resist excessive deformation during bonding and form a uniform and stable initial bonding interface. This also prevents stress concentration due to excessively high modulus or initial creep caused by excessively low modulus. When the temperature rises to 80°C due to the photo-thermal coupling effect, maintaining the storage modulus of the pressure-sensitive adhesive at 0.35 MPa to 0.6 MPa allows it to maintain necessary structural support and resistance to permanent deformation under long-term high-temperature conditions, effectively suppressing adhesive flow and migration. Simultaneously, this modulus range ensures appropriate flexibility, effectively buffering and dissipating interfacial thermal stress caused by differences in thermal expansion between components, preventing interfacial delamination failure.

[0019] Therefore, simultaneously controlling the storage modulus of the pressure-sensitive adhesive at 20℃ and 80℃ can ensure the continuity and controllability of its mechanical response throughout the entire operating temperature range, optimizing its morphological stability and stress management capabilities over a wide temperature range. Furthermore, combining this with the control of the loss factor and its peak temperature can further suppress adhesive migration and reduce the risk of residual adhesive during replacement.

[0020] To maintain a relatively constant loss factor, the loss modulus of the pressure-sensitive adhesive decreases with increasing temperature within the range of 20℃ to 80℃. Furthermore, within this range, if the difference between the maximum and minimum loss modulus of the pressure-sensitive adhesive is too large, its viscous behavior may become overly sensitive to temperature changes. Microscopically, the polymer chain segment movement becomes excessively active with increasing temperature. This leads to a significant decline in the cohesive strength of the pressure-sensitive adhesive in the high-temperature range. Under long-term photo-thermal coupling, the colloid is more prone to irreversible creep and flow, gradually migrating from the adhesive interface to the protective film surface, forming functional contamination.

[0021] Therefore, by controlling the difference between the maximum and minimum values ​​of the loss modulus to below 0.5 MPa, this application ensures that the tack response of the pressure-sensitive adhesive remains stable throughout the entire operating temperature range. Thus, even under extreme photothermal conditions approaching 80°C, the pressure-sensitive adhesive can still maintain effective cohesion and resistance to deformation, thereby significantly suppressing the tendency of the adhesive to migrate to the surface of the protective film.

[0022] Furthermore, this feature can be combined with the regulation of loss factor and peak temperature to ensure viscoelastic balance of initial bonding at a reference point of 20℃, avoid major aging sensitive areas through peak temperature design, and ensure high-temperature anti-migration performance by stabilizing the loss modulus over a wide temperature range. Thus, the three complement each other and effectively improve the long-term durability and reliability of pressure-sensitive adhesive under photo-thermal coupling conditions, fundamentally and simultaneously suppressing the occurrence of poor initial bonding, adhesive migration, and residual adhesive during replacement.

[0023] Furthermore, the pressure-sensitive adhesive has a loss modulus of 0.35 MPa to 0.6 MPa at 20°C, ensuring suitable viscous dissipation capacity during the initial bonding stage at room temperature. This promotes sufficient wetting and stress release of the photomask surface, resulting in a strong and reliable initial bond. Simultaneously, it avoids insufficient cohesion due to excessively high loss modulus or stress buffering due to excessively low loss modulus. When the temperature rises to 80°C due to the photo-thermal coupling effect, maintaining the loss modulus of the pressure-sensitive adhesive at 0.05 MPa to 0.15 MPa effectively suppresses excessive viscous flow and molecular chain relaxation under long-term high-temperature conditions. This significantly reduces the risk of colloid creep migration caused by thermal softening. Furthermore, this modulus range ensures that the pressure-sensitive adhesive maintains sufficient cohesive strength to resist long-term stress at high temperatures.

[0024] Therefore, simultaneously controlling the loss modulus of the pressure-sensitive adhesive (PSA) at 20℃ and 80℃ ensures the continuity and controllability of its viscous dissipation behavior and cohesive strength balance across the entire operating temperature range, optimizing its anti-flow properties and interfacial stability over a wide temperature spectrum. This characteristic, combined with the regulation of storage modulus, loss factor, and peak temperature, allows for the comprehensive optimization of the PSA's performance under photo-thermal coupling conditions from multiple viscoelastic dimensions, thereby more effectively suppressing adhesive migration and reducing the risk of residual adhesive during replacement.

[0025] When the storage modulus and loss modulus of the pressure-sensitive adhesive (PSA) are equal, the loss factor of the PSA is 1. This is a critical point where the viscoelastic behavior of the PSA undergoes a dominant transition. This point is the critical condition for the PSA to transition from a region dominated by elastic solid characteristics to a region enhanced by viscous liquid characteristics. In this application, the temperature at which the loss factor of the PSA equals 1 is controlled within the range of -10℃ to 0℃. This ensures that the viscoelastic transition point is outside the working temperature range of the photolithography process, thereby ensuring that the PSA maintains a stable state dominated by elastic behavior within the typical operating temperature range and effectively avoiding the risk of sudden performance changes due to the viscoelastic state transition.

[0026] This application also provides a method for preparing the pressure-sensitive adhesive for the photomask protection component, comprising the following steps:

[0027] By mass fraction, 20%–30% hydrogenated petroleum resin, 10%–20% white oil, 2%–5% crystalline polymer, and the balance styrene block copolymer thermoplastic elastomer are mixed at 220°C–230°C to obtain a mixture.

[0028] The mixture is first cooled to 100°C to 120°C within 5 to 10 minutes, and then cooled to 20°C within 20 to 30 minutes to obtain a pressure-sensitive adhesive.

[0029] In the preparation method of this application, styrene block copolymer thermoplastic elastomer is used as the main material. Its molecular structure can provide excellent resistance to ultraviolet aging and construct a stable three-dimensional network skeleton for the system. Hydrogenated petroleum resin is used as a tackifier, which can effectively improve the adhesion performance of the pressure-sensitive adhesive. By controlling the amount, sufficient interfacial adhesion can be ensured, while avoiding the risk of migration or residue caused by excessive addition leading to a decrease in cohesion. Since hydrogenated petroleum resin can reduce the overall modulus parameter of the pressure-sensitive adhesive and can regulate the peak temperature of the loss factor to shift downwards to higher temperatures, if the amount of hydrogenated petroleum resin used is too high, the peak temperature of the loss factor will be too high, and the storage energy and loss modulus will be relatively high. If the amount of hydrogenated petroleum resin used is too low, its storage energy and loss modulus will be relatively low, the interfacial adhesion will be insufficient, and the peak temperature will be too low, increasing the risk of residue.

[0030] White oil, acting as a softener and lubricant, can synergistically work with petroleum resins to optimize processing fluidity and jointly regulate the peak temperature of the pressure-sensitive adhesive's loss factor. Crystalline polymers can synergistically work with styrene block copolymers to significantly improve the modulus retention and morphological stability of pressure-sensitive adhesives at high temperatures. Especially in high-temperature environments, crystalline polymers can suppress the excessive decrease in storage modulus and loss modulus in the high-temperature region, thereby maintaining high-temperature cohesion, resisting colloid migration, and preventing residual adhesive.

[0031] Furthermore, mixing the above components at 220℃~230℃ first ensures that the high softening point hydrogenated petroleum resin and the highly crystalline polymer are fully melted and uniformly dispersed at the molecular level, which is beneficial for forming a uniform and stable colloid. Then, a specific segmented gradient cooling process is used to first cool the mixture from the reaction temperature to 100℃~120℃ within 5min~10min to quickly pass through the high-temperature crystallization zone and initially shape the network structure. Subsequently, it is slowly cooled to room temperature of 20℃ within 20min~30min. By controlling the cooling rate, the orderly arrangement and relaxation of polymer chain segments are effectively promoted, and internal thermal stress and structural defects are eliminated to the greatest extent, thereby obtaining a pressure-sensitive adhesive with a uniform cohesive structure and stable performance.

[0032] Therefore, by precisely designing the components and proportions, and by coordinating the control of mixing temperature and cooling process, the storage modulus, loss modulus, loss factor, and peak temperature of the loss factor of the pressure-sensitive adhesive can be made to be within the range of this application, so that the pressure-sensitive adhesive can simultaneously possess reliable initial bonding strength, excellent anti-migration ability, and clean peel performance under photo-thermal coupling conditions.

[0033] The styrene block copolymer thermoplastic elastomer is selected from at least one of SEBS, SBS, and SEPS.

[0034] Furthermore, the hydrogenated petroleum resin has a softening point greater than 120°C. Under photo-thermal coupling conditions, high-temperature environments easily cause the tackifying resin to soften or flow, leading to a decrease in the cohesive strength of the pressure-sensitive adhesive and inducing colloid migration. However, by using a hydrogenated petroleum resin with a softening point higher than 120°C, its heat distortion temperature is much higher than the local peak temperature in the photolithography process, thus maintaining stable solid-state properties under long-term high-temperature conditions. This characteristic effectively avoids abnormally high viscosity and decreased cohesive strength caused by resin thermal softening, significantly improving the overall heat resistance and high-temperature morphology retention of the pressure-sensitive adhesive system. Therefore, the introduction of a high-softening-point hydrogenated petroleum resin not only helps maintain the stability of the storage modulus and loss modulus of the pressure-sensitive adhesive in the high-temperature region, but also strengthens the colloid's anti-creep and anti-migration capabilities at the tackifying component level, which is beneficial for improving the long-term reliability of the pressure-sensitive adhesive under photo-thermal coupling conditions.

[0035] Furthermore, the crystallinity of the crystalline polymer is 50%–70%. Crystallinity is a key structural parameter that determines the polymer's ability to maintain its morphology and modulus at high temperatures. When the crystallinity is below 50%, the proportion of crystalline regions in the polymer is insufficient, resulting in a decrease in its hardness and modulus retention at high temperatures. This makes it difficult to effectively suppress the softening and deformation of the pressure-sensitive adhesive under photo-thermal coupling, which is detrimental to maintaining high-temperature cohesion. When the crystallinity is above 70%, the polymer becomes too rigid and its flexibility decreases significantly. This not only worsens the initial adhesion and wetting ability of the pressure-sensitive adhesive at room temperature but may also generate excessive internal stress at the interface, increasing the risk of peeling.

[0036] Therefore, this application controls the crystallinity within the range of 50% to 70%, which allows the crystalline polymer to maintain a certain degree of flexibility while possessing sufficient high-temperature rigidity and dimensional stability. At this crystallinity, the crystalline polymer can provide an effective supporting skeleton at high temperatures, significantly suppressing the excessive decrease in the overall storage modulus and loss modulus of the pressure-sensitive adhesive, thereby enhancing its creep resistance and migration resistance.

[0037] Furthermore, the crystalline polymer is selected from block polypropylene. Due to its unique sequence structure, block polypropylene can form crystalline regions with higher regularity and perfection during crystallization. This microstructural feature allows it to effectively improve the high-temperature energy storage modulus of the pressure-sensitive adhesive while retaining necessary local flexibility. More importantly, block polypropylene and styrene block copolymers have better compatibility at the molecular chain segment level, and the two can form a multiphase structure with stronger interfacial bonding and more uniform phase domain size. This stable microstructure allows the rigidity-enhancing effect of block polypropylene to be fully utilized. Therefore, selecting block polypropylene not only provides an effective heat-resistant support network through its own highly regular crystalline regions, but also achieves efficient improvement of matrix rigidity by optimizing the phase interface. Compared with homopolymer polypropylene or other crystalline polymers, block polypropylene can more significantly improve the modulus retention, creep resistance, and cohesive strength of the pressure-sensitive adhesive at high temperatures, thereby enhancing its long-term morphological stability under photo-thermal coupling conditions.

[0038] This application also provides a photomask protection component, including a protection component and a pressure-sensitive adhesive layer disposed on the surface of the protection component for bonding with a photomask, wherein the pressure-sensitive adhesive layer is the aforementioned pressure-sensitive adhesive.

[0039] Therefore, when used in a lithography machine, this photomask protection component can maintain stable performance under the harsh conditions of internal photo-thermal coupling. The pressure-sensitive adhesive layer will not undergo significant performance degradation due to long-term light and heat effects. It can effectively prevent the adhesive from migrating to the photomask functional area and ensure that the pressure-sensitive adhesive layer is completely peeled off from the photomask surface without leaving any residue when the protection component needs to be replaced. Attached Figure Description

[0040] The following description, in conjunction with the accompanying drawings, further illustrates this application:

[0041] Figure 1 The loss factor diagram of the pressure-sensitive adhesive prepared in Example 1 of the present invention;

[0042] Figure 2 This is a storage modulus diagram of the pressure-sensitive adhesive prepared in Example 1 of the present invention;

[0043] Figure 3 The loss modulus diagram is shown for the pressure-sensitive adhesive prepared in Example 1 of this invention.

[0044] Figure 4 The loss factor diagram is shown for the pressure-sensitive adhesive prepared in Comparative Example 1 of this invention.

[0045] Figure 5 The storage modulus diagram is shown for the pressure-sensitive adhesive prepared in Comparative Example 1 of this invention.

[0046] Figure 6 The loss modulus diagram is shown for the pressure-sensitive adhesive prepared in Comparative Example 1 of this invention.

[0047] Figure 7 This is a schematic diagram of the structure of the photomask protection component of the present invention, wherein 10 is the protection component, 11 is the photomask, and 12 is the pressure-sensitive adhesive layer. Detailed Implementation

[0048] To more clearly illustrate the overall concept of this application, the following detailed description is provided in conjunction with embodiments. Unless otherwise specified, the raw materials and equipment used in the preparation in the following embodiments are commercially available.

[0049] Example 1

[0050] By mass fraction, 25% hydrogenated petroleum resin (brand name SUNTACK 140 / R, softening point 140℃), 16% white oil, 3% block polypropylene (crystallinity 62%), and the balance SEBS were mixed at 224℃ to obtain a mixture. The mixture was then cooled to 117℃ over 6 minutes, and then to 20℃ over 25 minutes to obtain a pressure-sensitive adhesive.

[0051] Example 2

[0052] By mass fraction, 27% hydrogenated petroleum resin (brand name SUNTACK 130 / R, softening point 130℃), 13% white oil, 3% block polypropylene (crystallinity 57%), and the balance SEBS were mixed at 226℃ to obtain a mixture. The mixture was then cooled to 106℃ over 8 minutes, and then to 20℃ over 27 minutes to obtain a pressure-sensitive adhesive.

[0053] Example 3

[0054] By mass fraction, 30% hydrogenated petroleum resin (brand name SUNTACK 130 / R, softening point 130℃), 10% white oil, 2% block polypropylene (crystallinity 51%), and the balance SEBS were mixed at 220℃ to obtain a mixture. The mixture was then cooled to 102℃ over 10 minutes, and then to 20℃ over 30 minutes to obtain a pressure-sensitive adhesive.

[0055] Example 4

[0056] By mass fraction, 23% hydrogenated petroleum resin (brand name SUNTACK 140 / R, softening point 140℃), 17% white oil, 4% block polypropylene (crystallinity 64%), and the balance SEBS were mixed at 227℃ to obtain a mixture. The mixture was then cooled to 115℃ over 6 minutes, and then to 20℃ over 23 minutes to obtain a pressure-sensitive adhesive.

[0057] Example 5

[0058] By mass fraction, 21% hydrogenated petroleum resin (brand name SUNTACK 140 / R, softening point 140℃), 19% white oil, 5% block polypropylene (crystallinity 68%), and the balance SEBS were mixed at 230℃ to obtain a mixture. The mixture was then cooled to 120℃ over 5 minutes, and then to 20℃ over 20 minutes to obtain a pressure-sensitive adhesive.

[0059] Example 6

[0060] By mass fraction, 22% hydrogenated petroleum resin (brand name SUNTACK 140 / R, softening point 140℃), 17% white oil, 5% block polypropylene (crystallinity 77%), and the balance SEBS were mixed at 229℃ to obtain a mixture. The mixture was then cooled to 112℃ over 7 minutes, and then to 20℃ over 20 minutes to obtain a pressure-sensitive adhesive.

[0061] Example 7

[0062] By mass fraction, 29% hydrogenated petroleum resin (brand name SUNTACK 100 / R, softening point 100℃), 12% white oil, 2% block polypropylene (crystallinity 53%), and the balance SEBS were mixed at 220℃ to obtain a mixture. The mixture was then cooled to 105℃ over 10 minutes, and then to 20℃ over 25 minutes to obtain a pressure-sensitive adhesive.

[0063] Example 8

[0064] By mass fraction, 29% hydrogenated petroleum resin (brand name SUNTACK 130 / R, softening point 130℃), 11% white oil, 2% block polypropylene (crystallinity 42%), and the balance SEBS were mixed at 221℃ to obtain a mixture. The mixture was then cooled to 102℃ over 10 minutes, and then to 20℃ over 30 minutes to obtain a pressure-sensitive adhesive.

[0065] Example 9

[0066] By mass fraction, 28% hydrogenated petroleum resin (brand name SUNTACK 140 / R, softening point 140℃), 10% white oil, 2% block polypropylene (crystallinity 44%), and the balance SEBS were mixed at 222℃ to obtain a mixture. The mixture was then cooled to 107℃ over 8 minutes, and then to 20℃ over 28 minutes to obtain a pressure-sensitive adhesive.

[0067] Example 10

[0068] By mass fraction, 30% hydrogenated petroleum resin (brand name SUNTACK 140 / R, softening point 140℃), 13% white oil, 2% block polypropylene (crystallinity 44%), and the balance SEBS were mixed at 225℃ to obtain a mixture. The mixture was then cooled by 20℃ over 50 minutes to obtain a pressure-sensitive adhesive.

[0069] Comparative Example 1

[0070] By mass fraction, 34% hydrogenated petroleum resin (brand name SUNTACK 130 / R, softening point 130℃), 7% white oil, 2% block polypropylene (crystallinity 58%), and the balance SEBS were mixed at 220℃ to obtain a mixture. The mixture was then cooled to 105℃ over 10 minutes, and then to 20℃ over 25 minutes to obtain a pressure-sensitive adhesive.

[0071] Comparative Example 2

[0072] By mass fraction, 41% hydrogenated petroleum resin (brand name SUNTACK 130 / R, softening point 130℃), 3% white oil, 4% block polypropylene (crystallinity 63%), and the balance SEBS were mixed at 225℃ to obtain a mixture. The mixture was then cooled to 20℃ over 50 minutes to obtain a pressure-sensitive adhesive.

[0073] Comparative Example 3

[0074] By mass fraction, 18% hydrogenated petroleum resin (brand name SUNTACK 130 / R, softening point 130℃), 23% white oil, 3% block polypropylene (crystallinity 61%), and the balance SEBS were mixed at 225℃ to obtain a mixture. The mixture was then cooled to 20℃ within 10 minutes to obtain a pressure-sensitive adhesive.

[0075] Comparative Example 4

[0076] By mass fraction, 12% hydrogenated petroleum resin (brand name SUNTACK 130 / R, softening point 130℃), 27% white oil, and the balance SEBS were mixed at 225℃ to obtain a mixture. The mixture was then heated at 20℃ for 10 minutes to obtain a pressure-sensitive adhesive.

[0077] The pressure-sensitive adhesives of the above embodiments and comparative examples were subjected to DMA (Dynamic Thermomechanical Analysis) tests. The test results for Example 1 are shown below. Figures 1-3 As shown, the test chart for Comparative Example 1 is as follows. Figures 4-6 As shown, the data is as follows.

[0078] Example 1:

[0079] The loss factor at 20℃ is 0.224, the peak temperature of the loss factor is -17.5℃, the peak value A is 1.43, the maximum difference in loss factor between 20℃ and 80℃ is 0.09, the temperature at which the loss factor equals 1 is -6.26℃, the energy storage modulus at 20℃ is 2.14 MPa, the energy storage modulus at 80℃ is 0.59 MPa, and the maximum difference in energy storage modulus between 20℃ and 80℃ is 1.55 MPa; the loss modulus at 20℃ is 0.48 MPa, the loss modulus at 80℃ is 0.1 MPa, and the maximum difference in loss modulus between 20℃ and 80℃ is 0.38 MPa.

[0080] Example 2:

[0081] The loss factor at 20℃ is 0.254, the peak temperature of the loss factor is -14.3℃, the peak value A is 1.47, the maximum difference in loss factor between 20℃ and 80℃ is 0.1, the temperature at which the loss factor equals 1 is -4.7℃, the energy storage modulus at 20℃ is 1.73 MPa, the energy storage modulus at 80℃ is 0.56 MPa, and the maximum difference in energy storage modulus between 20℃ and 80℃ is 1.17 MPa; the loss modulus at 20℃ is 0.44 MPa, the loss modulus at 80℃ is 0.09 MPa, and the maximum difference in loss modulus between 20℃ and 80℃ is 0.35 MPa.

[0082] Example 3:

[0083] The loss factor at 20℃ is 0.345, the peak temperature of the loss factor is -11.3℃, the peak value A is 1.49, the maximum difference in loss factor between 20℃ and 80℃ is 0.12, the temperature at which the loss factor equals 1 is -0.3℃, the energy storage modulus at 20℃ is 1.1 MPa, the energy storage modulus at 80℃ is 0.51 MPa, and the maximum difference in energy storage modulus between 20℃ and 80℃ is 0.59 MPa; the loss modulus at 20℃ is 0.38 MPa, the loss modulus at 80℃ is 0.06 MPa, and the maximum difference in loss modulus between 20℃ and 80℃ is 0.32 MPa.

[0084] Example 4:

[0085] The loss factor at 20℃ is 0.209, the peak temperature of the loss factor is -24.2℃, the peak value A is 1.28, the maximum difference in loss factor between 20℃ and 80℃ is 0.07, the temperature at which the loss factor equals 1 is -8.6℃, the energy storage modulus at 20℃ is 2.58 MPa, the energy storage modulus at 80℃ is 0.61 MPa, and the maximum difference in energy storage modulus between 20℃ and 80℃ is 1.97 MPa; the loss modulus at 20℃ is 0.54 MPa, the loss modulus at 80℃ is 0.12 MPa, and the maximum difference in loss modulus between 20℃ and 80℃ is 0.42 MPa.

[0086] Example 5:

[0087] The loss factor at 20℃ is 0.191, the peak temperature of the loss factor is -28.7℃, the peak value A is 1.04, the maximum difference in loss factor between 20℃ and 80℃ is 0.05, the temperature at which the loss factor equals 1 is -9.5℃, the energy storage modulus at 20℃ is 3.03 MPa, the energy storage modulus at 80℃ is 0.63 MPa, and the maximum difference in energy storage modulus between 20℃ and 80℃ is 2.4 MPa; the loss modulus at 20℃ is 0.58 MPa, the loss modulus at 80℃ is 0.13 MPa, and the maximum difference in loss modulus between 20℃ and 80℃ is 0.45 MPa.

[0088] Example 6:

[0089] The loss factor at 20℃ is 0.209, the peak temperature of the loss factor is -27.3℃, the peak value A is 1.08, the maximum difference in loss factor between 20℃ and 80℃ is 0.07, the temperature at which the loss factor equals 1 is -10.5℃, the energy storage modulus at 20℃ is 3.2 MPa, the energy storage modulus at 80℃ is 0.65 MPa, and the maximum difference in energy storage modulus between 20℃ and 80℃ is 2.55 MPa; the loss modulus at 20℃ is 0.67 MPa, the loss modulus at 80℃ is 0.14 MPa, and the maximum difference in loss modulus between 20℃ and 80℃ is 0.53 MPa.

[0090] Example 7:

[0091] The loss factor at 20℃ is 0.338, the peak temperature of the loss factor is -11.3℃, the peak value A is 1.47, the maximum difference in loss factor between 20℃ and 80℃ is 0.11, the temperature at which the loss factor equals 1 is -2.3℃, the energy storage modulus at 20℃ is 0.8 MPa, the energy storage modulus at 80℃ is 0.42 MPa, and the maximum difference in energy storage modulus between 20℃ and 80℃ is 0.38 MPa; the loss modulus at 20℃ is 0.27 MPa, the loss modulus at 80℃ is 0.03 MPa, and the maximum difference in loss modulus between 20℃ and 80℃ is 0.24 MPa.

[0092] Example 8:

[0093] The loss factor at 20℃ is 0.333, the peak temperature of the loss factor is -12.4℃, the peak value A is 1.47, the maximum difference in loss factor between 20℃ and 80℃ is 0.11, the temperature at which the loss factor equals 1 is -0.4℃, the energy storage modulus at 20℃ is 1.2 MPa, the energy storage modulus at 80℃ is 0.48 MPa, and the maximum difference in energy storage modulus between 20℃ and 80℃ is 0.72 MPa; the loss modulus at 20℃ is 0.4 MPa, the loss modulus at 80℃ is 0.03 MPa, and the maximum difference in loss modulus between 20℃ and 80℃ is 0.37 MPa.

[0094] Example 9:

[0095] The loss factor at 20℃ is 0.308, the peak temperature of the loss factor is -14.2℃, the peak value A is 1.58, the maximum difference in loss factor between 20℃ and 80℃ is 0.12, the temperature at which the loss factor equals 1 is -0.7℃, the energy storage modulus at 20℃ is 1.2 MPa, the energy storage modulus at 80℃ is 0.54 MPa, and the maximum difference in energy storage modulus between 20℃ and 80℃ is 0.66 MPa; the loss modulus at 20℃ is 0.37 MPa, the loss modulus at 80℃ is 0.07 MPa, and the maximum difference in loss modulus between 20℃ and 80℃ is 0.3 MPa.

[0096] Example 10:

[0097] The loss factor at 20℃ is 0.320, the peak temperature of the loss factor is -12.2℃, the peak value A is 1.62, the maximum difference in loss factor between 20℃ and 80℃ is 0.18, the temperature at which the loss factor equals 1 is -1.3℃, the energy storage modulus at 20℃ is 1.03 MPa, the energy storage modulus at 80℃ is 0.45 MPa, and the maximum difference in energy storage modulus between 20℃ and 80℃ is 0.58 MPa; the loss modulus at 20℃ is 0.33 MPa, the loss modulus at 80℃ is 0.04 MPa, and the maximum difference in loss modulus between 20℃ and 80℃ is 0.29 MPa.

[0098] Comparative Example 1: The loss factor at 20℃ is 0.612, and the peak temperature of the loss factor is -0.2℃.

[0099] Comparative Example 2: The loss factor at 20℃ is 0.831, and the peak temperature of the loss factor is 8.3℃.

[0100] Comparative Example 3: The loss factor at 20℃ is 0.172, and the peak temperature of the loss factor is -38.9℃.

[0101] Comparative Example 4: The loss factor at 20℃ is 0.134, and the peak temperature of the loss factor is -45.2℃.

[0102] Peel strength and residual adhesive tests were conducted on the pressure-sensitive adhesives used in the above embodiments and comparative examples, as shown in Table 1. The peel strength (N) test method was as follows: a hole was drilled along the long side of one side of the aluminum frame. After applying the pressure-sensitive adhesive, the sample was attached to the glass substrate under the following conditions (applied pressure: 250N, holding time: 5mins). The glass substrate was fixed in place. One end of an iron ring was passed through the hole in the aluminum frame, and the other end was attached to the hook of a tension gauge. The tension gauge was rotated until the aluminum frame completely detached from the glass substrate. The resulting reading was defined as the peel strength of the pressure-sensitive adhesive. The residual adhesive test method was to measure the weight change of the glass substrate before and after the test and calculate the percentage.

[0103] Table 1

[0104]

[0105]

[0106] As can be seen from the table above, by precisely controlling the viscoelasticity of the pressure-sensitive adhesive in Examples 1-5 of this application, the pressure-sensitive adhesive can exhibit excellent peel performance in the range of 20℃ to 80℃, and there is no adhesive residue.

[0107] In contrast, Example 6, due to the use of highly crystalline block polypropylene, exhibits higher storage modulus and loss modulus at 20°C, resulting in relatively lower peel performance between 20°C and 80°C, but with no residual adhesive. Example 7, employing hydrogenated petroleum resin with a lower softening point, shows lower storage modulus and loss modulus at both 20°C and 80°C, thus resulting in relatively lower peel performance between 20°C and 80°C, but with no residual adhesive. In Examples 8-10, the block polypropylene used has lower crystallinity. Under different preparation parameters, Example 8 exhibits lower storage modulus and loss modulus at 80°C, Example 9 shows a lower peak loss factor A, and Example 10 shows a higher loss factor difference, resulting in lower storage modulus at 80°C and lower loss modulus at both 20°C and 80°C, thus resulting in relatively lower peel performance between 20°C and 80°C, but with no residual adhesive.

[0108] In Comparative Examples 1 and 2, the excessive use of hydrogenated petroleum resin resulted in slow cooling during preparation, leading to excessively high loss factors and peak temperatures at 20°C. In Comparative Examples 3 and 4, the excessively low use of hydrogenated petroleum resin resulted in rapid cooling during preparation, leading to excessively low loss factors and peak temperatures at 20°C. Consequently, the pressure-sensitive adhesives of Comparative Examples 1-4 exhibited excessively low peel performance between 20°C and 80°C, and left residual adhesive, rendering them unusable.

[0109] The pressure-sensitive adhesive of this application is mainly used in photomask protection components, such as... Figure 7 As shown, the photomask protection assembly includes a protection component 10 and a pressure-sensitive adhesive layer 12 disposed on the surface of the protection component 10 for bonding with the photomask 11. The pressure-sensitive adhesive layer 12 uses the aforementioned pressure-sensitive adhesive. The protection component 10 may include an aluminum frame in direct contact with the pressure-sensitive adhesive and a photomask protective film disposed on the other side. The photomask protective film and the aluminum frame can also be bonded and fixed using the pressure-sensitive adhesive of this application. During use, because the pressure-sensitive adhesive of this application maintains long-term performance stability under photo-thermal coupling conditions, the pressure-sensitive adhesive layer 12 will not experience significant performance degradation due to long-term light and heat effects when used in a lithography machine. This effectively prevents the adhesive from migrating to the functional areas of the photomask 11 and ensures that the pressure-sensitive adhesive layer 12 is completely peeled off from the photomask surface without leaving any residue when the protection component 10 needs to be replaced.

[0110] The above only introduces the content related to the inventive point; the rest can be obtained by referring to relevant technologies, and will not be described in detail here.

[0111] The above embodiments merely illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A pressure-sensitive adhesive for a photomask protection component, characterized in that, The pressure-sensitive adhesive includes a styrene block copolymer thermoplastic elastomer. The loss factor of the pressure-sensitive adhesive at 20°C is 0.19 to 0.35, and the peak temperature of the loss factor is -30°C to -10°C.

2. The pressure-sensitive adhesive for the photomask protection assembly according to claim 1, characterized in that, The peak value of the loss factor is A, where 1 < A < 1.

5.

3. The pressure-sensitive adhesive for the photomask protection component according to claim 1, characterized in that, Within the temperature range of 20℃ to 80℃, the difference in loss factor is less than 0.

13.

4. The pressure-sensitive adhesive for the photomask protection assembly according to claim 1, characterized in that, Within the temperature range of 20℃ to 80℃, the storage modulus of the pressure-sensitive adhesive decreases with increasing temperature, and the difference between the maximum and minimum storage modulus of the pressure-sensitive adhesive is less than 2.5 MPa.

5. The pressure-sensitive adhesive for the photomask protection assembly according to claim 4, characterized in that, Within the temperature range of 20℃ to 80℃, the loss modulus of the pressure-sensitive adhesive decreases with increasing temperature, and the difference between the maximum and minimum loss modulus of the pressure-sensitive adhesive is less than 0.5MPa.

6. The pressure-sensitive adhesive for the photomask protection assembly according to claim 1, characterized in that, The pressure-sensitive adhesive has a storage modulus of 1 MPa to 3.1 MPa at 20°C and a storage modulus of 0.5 MPa to 0.65 MPa at 80°C.

7. The pressure-sensitive adhesive for the photomask protection assembly according to claim 1, characterized in that, The pressure-sensitive adhesive has a loss modulus of 0.35MPa to 0.6MPa at 20℃ and a loss modulus of 0.05MPa to 0.15MPa at 80℃.

8. The pressure-sensitive adhesive for the photomask protection assembly according to claim 1, characterized in that, The temperature at which the loss factor of the pressure-sensitive adhesive is equal to 1 is within the range of -10℃ to 0℃.

9. A method for preparing a pressure-sensitive adhesive for a photomask protection component as described in any one of claims 1 to 8, characterized in that, Includes the following steps: By mass fraction, 20%–30% hydrogenated petroleum resin, 10%–20% white oil, 2%–5% crystalline polymer, and the balance styrene block copolymer thermoplastic elastomer are mixed at 220°C–230°C to obtain a mixture. The mixture is first cooled to 100°C to 120°C within 5 to 10 minutes, and then cooled to 20°C within 20 to 30 minutes to obtain a pressure-sensitive adhesive.

10. The method for preparing pressure-sensitive adhesive for photomask protection components according to claim 9, characterized in that, The softening point of the hydrogenated petroleum resin is greater than 120°C. And / or, the crystallinity of the crystalline polymer is 50% to 70%; And / or, the crystalline polymer is selected from block polypropylene; And / or, the styrene block copolymer thermoplastic elastomer is selected from at least one of SEBS, SBS, and SEPS.

11. A photomask protection assembly, comprising a protection assembly and a pressure-sensitive adhesive layer disposed on the surface of the protection assembly for bonding with a photomask, characterized in that, The pressure-sensitive adhesive layer is made of the pressure-sensitive adhesive as described in any one of claims 1 to 8.

Images