TWI230145B - Substrate glass for plate panel display - Google Patents

Abstract

The invention relates to an alkali-free aluminoborosilicate glass which has the following composition in % by weight, based on oxide: 55-70 wt% SiO2, 10-18 wt% Al2O3, 8-15 wt% B2O3, 0-10 wt% CaO, 0-4 wt% SrO, 0.01-10 wt% La2O3. The feature of this invention is to provide glass which satisfy the said physical and thermal requirements of glass substrate for flat panel display. The feature is achieved by addition of La2O3 in the range of 0.01 to 15 wt%. The aluminoborosilicate glass with specific modulus greater than 31.0x10<6> (m/s)<2>, the strain point above 680 DEG C, and the thermal expansion coefficient as low as 31x10<-7>/DEG C were achieved.

Description

1230145 V. Description of the invention (1) Field of the invention The present invention relates to an alkali-free glass which is light in weight and has a low specific gravity 'and has a high specific modulus value, a low coefficient of thermal expansion and a high strain point and For chemical properties, it is especially suitable for substrate glass of flat display. BACKGROUND OF THE INVENTION The role played is becoming more and more popular, and products with thin and light flat displays are used to produce flat displays. The thinnest and lightest flat panel display manufacturers can reduce the weight of their panels, reduce costs and mass production. The standard for cutting under the same process is the third generation, but the latest technology should be developed towards larger sizes. The factors are as follows: (1) With high heat and stability In a highly information-oriented society, flat-panel displays are important. Computers, mobile phones and related equipment will be rapidly transformed, flattened, full-colored, and high-color contrast will be more market-oriented. accept. In such a trend, Weishang has become more enthusiastic about the development of thin and light panels. The direct method is to reduce the thickness of the substrate, so the demand for thin substrate glass has increased greatly, with a view to the amount. At the same time, due to the popularity of flat-panel displays, it has become one of the manufacturers' competitive strategies. If you want to reduce it, you must first increase the size of the substrate glass in order to increase the number of panels to increase the production capacity. Today's commonly used (550 mm * 650 mm) 3.5th generation (60 0ππη * 7 2 0 ππη) has reached the fifth generation (1100mm * 1250mm), and has a trend of. Therefore, glass has become a trend for substrate glass manufacturers. High glass strain temperature needs to be considered when manufacturing flat display substrate glass

Page 5 1230145

(2) has a closer thermal expansion coefficient to silicon crystals to open the possibility of chip on glass (Chip On Glass); (3) chemical resistance allows the process to be used under severe etching conditions (4) No alkali metal ions migrate out of the glass surface and damage elements such as transistors. In the prior art US482480 8 (Corning Glass Works), an alkali-free glass composition is provided. The glass composition has a higher melt viscosity and a strain point than that of US4994415 (Nippon Electric Glass Co., Ltd.). Acid glass. In the glass composition of this patent, 镙 is the main component, and IS is a very expensive substance, so if possible, the use of the alkali-free glass composition of the patent 0 ϋ S 5 1 1 6 7 8 7 should be avoided. Both have high strain points, but their long-term resistance to crystallization is low, and the thermal expansion coefficient is too high to match the thermal expansion coefficient of silicon. US 5 1 1 6 7 8 9 patent shows that its glass composition has the characteristics of high strain point, but the expansion coefficient is too high to match Shi Xi at the formed high temperature US 6 1 2 8 9 2 4, US 6 3 1 9 8 6 7 (Corning Glass Works) proposed a non-inspection glass composition with excellent substrate glass characteristics, but it failed to effectively increase the specific Young's modulus. Summary of invention

1230145 V. Description of the invention (3) The idea of the present invention is to use La20 to have small and highly charged ions (smai 1 highly charged ions), which can easily increase the characteristics of the glass network structure, which can make the glass substrate have a very high Young's modulus (Specific Young's modulus). And adjust the glass oxide composition so that the glass has high heat resistance and low coefficient of thermal expansion (Cefficent Thermal Expansion, CTE), and at the same time has chemical resistance. Object of the invention The composition of the present invention. The present invention has a higher composition than the strain point of the present invention. The flat display of the present invention is designed to remove the glass of the method of the present invention. The purpose is to provide a glass with a lower thermal expansion coefficient. In addition to the lower thermal expansion coefficient, it also has a glass composition with a change point. The purpose is to provide glass that has a lower thermal expansion coefficient, a higher Young's modulus and a higher Young's modulus than the Young's modulus can effectively reduce the stress on the glass. Another purpose is to provide substrate glass to which the glass composition can be applied. A further object is to provide industrial safety and environmental protection issues caused by barium oxide, a glass component group that does not have barium oxide. Another object is to provide a component composition that is also applicable to glass melt overflow. SUMMARY OF THE INVENTION The glass composition used in advanced flat panel displays must meet certain requirements.

Page 7 1230145 V. Description of the invention (4)

Strict standards. A liquid crystal display device equipped with a transistor, and a thin film transistor (Thin Film Transistor) is formed directly on a glass sheet. Thin-film transistors are generally formed on substrate glass that has been pre-treated to form a layer of polysilicon on the surface. Generally speaking, the formation of such polysilicon layers on substrate glass is processed at high temperature, that is, the glass composition used as the device substrate must have a relatively high strain point temperature to avoid glass changes during high temperature processing. Affect yield. The temperature of the strain point of a typical thin-film transistor liquid crystal display substrate glass needs to be at least 600 ° C, preferably more than 63 ° C. And because Shi Xi is directly generated on glass and needs high temperature treatment, the expansion coefficient of glass must be matched with silicon. When thin film transistors are formed on glass substrates using conventional semiconductor processes, these processes include sputtering, vapor deposition (CVD), photolithography processes, and etching. In these processes, the substrate glass is depleted by a large number of pharmaceuticals, washed, etched, Heat treatment, these drugs include strong acid reagents such as hydrofluoric acid, so the glass needs to have strong chemical resistance to avoid the precipitation of its components. In addition, the glass-breaking composition needs to be completely free of alkali metal ions to prevent diffusion to the transistor and cause deterioration of the characteristics of the display panel. To sum up, plus the glass composition needs to be able to withstand the melting and forming processes required in the flat glass manufacturing process, and the trend of the quality of g ^ month _ j low-cost large-scale production bureau 'sees the required substrate slope 3 ^ &amp; The product must have the following characteristics:

(1) Strain point above 63 ° C. (2) Low thermal expansion coefficient (close to the crushed expansion coefficient). (3) Strong chemical resistance. (4) Free of alkali metal ions (raw materials without special addition of alkali metal oxides)

1230145 V. Description of the invention (5) (5) South quality and suitable for mass production. At present, the main substrate glass manufacturing processes can be divided into three categories: Over-flow Fusion Process, Floating / Tin Bath Process, and Slit-down Draw Process. Among them, the melt-flow pull-down process is the most favorable for the finished product yield, unit cost, and mass production speed. However, with the tendency of the substrate glass to go to a large size, in the drawing process after the glass composition is melted and melted, the large-sized substrate glass is heavier and prone to sagging. In some cases, a completely flat, high-quality glass cannot be formed. In the manufacturing and transmission process of the flat panel display, the stress of large-size mother glass is one of the good effects. Because the substrate glass must be affected by external forces or gravity during the transportation process, if the substrate glass itself is not sufficiently hard and the residual stress is too large, sagging will occur during the transportation or transportation process, resulting in glass Problems such as cracking have seriously affected production yield. Therefore, improving the vertical flow phenomenon and glass stress have become the key technologies for the production of large-size substrate glass. The factors that cause the phenomenon of vertical flow and the ratio of Young's modulus (Young, smodulus) to density (also known as specific Young's modulus or specific modulus = E / p, p is the density and is Young's modulus Number) related. The Young's modulus is inversely proportional to the vertical flow phenomenon, that is, the smaller the p, the larger the Young's modulus, the more unclear the vertical flow phenomenon is. U is expressed by the following formula, and the amount of stress of the glass itself can be W = K (p / E) (L / t2)

1230145 __________________________ _ — ___________-_____ ^ __ »V. Description of the invention (6) (P is density, E is Young's modulus, L is glass length't is glass thickness) It can be seen that the stress of glass and the square of its thickness Inversely proportional to length. As the thickness of the glass decreases and its size increases, its stress will increase. Therefore, in order to reduce the residual stress and reduce the risk of glass breakage in order to improve the yield, in addition to improving the machine design of the flat panel display production line, the physical properties of the substrate glass need to be improved. It can be known from the above formula that the ratio of the density P to the Young's modulus E, that is, the inverse of the Young's modulus determines the stress physical properties of the glass. If the p / E of the glass is small, the stress of the glass also decreases. To sum up, if you want to improve the physical properties of glass so that it does not produce vertical flow in the glass forming process, and the residual stress is small, and it is not easy to break in the display panel manufacturing, you need to start with its Young's modulus and density. In the current glass composition formula, it already has a relatively small density. Therefore, if the Young's modulus of the glass can be increased, the flat display substrate glass can be thin, light, and free from the phenomenon of vertical flow. The traditional composition that meets the basic requirements of substrate glass is borosilicate silicate glass R0-R2 (VSi02. Among them, R0 represents an alkaline earth metal oxide selected from MgO, CaO, SrO, BaO, and R 20 represents B 2 〇 and A 1 20 A trivalent oxides, but neither of them can effectively increase the Young's modulus of glass. In the present invention, in the glass composition, the addition of trioxide, i ^ a ^ O 3, because La 20 has a small Moreover, high charge ions can easily increase the characteristics of the glass network structure, can significantly increase the Young's modulus, increase the specific modulus, and because of its excellent heat resistance, it can also increase the strain point of glass breaking. The experimental methods, influences, and effects of the composition limit of each component of the glass are explained separately as follows: The research and experimental process of the composition of the glass composition is a formula designed by each

1230145 V. Description of the invention (7) Weigh and grind to help produce a homogeneous melt ^ The knife is made of sigma σ and evenly mixed, added to the platinum hanging pot, and placed in the high temperature. The refining temperature reaches 16 According to different groups = = to find the melting, mechanically use a platinum stirring rod, stir and homogenize for about 30 minutes. After pouring out and injection molding, precision cooling is performed. Although the above explains the melting step of the experiment, it must be paid attention to that the glass of the present invention is sufficient to melt and manufacture using large-scale commercial melting and manufacturing equipment. . Antimony trioxide Sb203 (also used trioxane, arsenic As200 as a clarifying agent) was added to the experimental melt, and it was added to the raw materials in a proportion of an appropriate minimum amount, and the amount retained in glass A small portion of the residue has essentially no effect on the properties of the glass.

SiO 2 (silicon dioxide), which is one of the main bodies of glass. Although high content of S 1 0 can achieve the purpose of lightweight and low thermal expansion of glass, it will increase the processing temperature and processing time of melting, resulting in waste of energy and Yield decreases, and too low S i 0 2 will cause devitrification to affect display quality, and the glass's chemical strength will deteriorate. Therefore, in the present invention, the content of si 0 夂 is 50% to 70% by weight. . ', L a 2 0 from lanthanum trioxide) ... lanthanum trioxide has small highly charged ions, which is easy to increase the characteristics of the glass network structure.' It can be understood from the experiment in Table 1 below The effect of La 2〇 on glass composition. Increasing the content of La 2〇 夂 from 0% to 16% has the effect of increasing Young's modulus, increasing Young's modulus and strain point. From this series of experiments, La 2 03

1230145 V. Description of the invention (8) The ideal content is 2wt% ~ 14wt%. Alkaline earth metal oxide (R0): The alkaline earth metal oxide R0 component provides the cations required for glass melting and formation of a single-phase melt, but the high concentration of the oxide of the R0 type will cause the thermal expansion coefficient of the resulting glass composition. (C0effi cent Thermal Expansion, CTE) is too high, so that the resulting glass is not suitable for the manufacture of silicon-based thin-film transistor liquid crystal displays. On the other hand, if the total amount of alkaline earth metal oxides is too low, the glass melt viscosity can only increase the content of boron oxide B 2 0 夂 to maintain a low value, and the result of the glass's chemical resistance. The oxides of all alkaline earth metals reduce the melting viscosity of glass by about the same degree. However, barium oxide is more likely to increase the coefficient of thermal expansion, and its powder is harmful, which may cause industrial safety and environmental protection problems. The thermal expansion coefficient of magnesium oxide MgO is only half of the increase of Ba0, but too much MgO will cause phase separation and devitrification when the melt is cooled. In addition, BeO exists in nature in a small amount, is highly toxic, and sr0 is not cheap. Therefore, the inventors balanced the type oxides in the composition without using barium oxide to reduce the glass CTE without causing phase separation. Trivalent oxide R203: Trivalent oxides (R203) such as A1203 and B20 舁 are the main components of the glass composition of the present invention. B203 can reduce glass melting Viscosity, without increasing the coefficient of expansion, an appropriate amount of B203 can increase the resistance to hydrofluoric acid 'and make it easy to process. And it is easy to process, but when the concentration of B 20 is too high, the acid resistance of the glass is impaired, and the change point is too low. A 1 2〇 Including

* I 1230145 V. Description of the invention (9) The amount is the main key to lower the liquid temperature. However, when the concentration of A 1 20 is too high or too low, the liquid temperature will increase. The above components were adjusted to make glass, and various characteristics were measured. The results are shown in Table 1. Take a look at the table, and based on the comprehensive consideration of chemical, physical and melting characteristics, the excellent composition of the present invention has a content limit of 55-7 0 wt% Si02, 10-18 wt% Al203, 8 -15 wt% B2〇3, 0-10 wt% CaO, 0-4 wt% SrO, 0-3 wt% MgO, 3-20 wt% CaO + SrO + MgO &quot; 0.01-10 wt% La2〇3 ° •

Page 13 1230145 V. Description of the invention (10) Table 1 Component wt ° / o wood wt% ^ wt% * wt% this wf / o * Si〇2 56.50 56.50 56.50 58.50 58.50 60.50 63.00 65.00 ΑΙΑ 15.00 15.00 15.00 15.00 15.50 15.50 15.00 15.00 BA 11.00 11.00 13.00 11.00 10.50 10.50 10.50 10.50 Ca〇4.60 4.60 4.60 4.60 6.60 6.60 6.60 4.60 Mg〇0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 Ba〇10.00 8.00 6.00 6.00 4.00 2.00 0,00 0.00 SrO 2,00 -2JDp 2.00 2.00 2.00 2.00 2.00 0.5 LaA 丨] 〇x x 〇〇2.00 2.00 2.00 2.00 2.00 3.5 SbA 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 Young's Modulus Gpa 72.05 75.72 71.83 73.27 74.27 75.78 75.20 75.82 Density (g / cm3) 2.5120 2.5621 2.5054 2.5110 2.4712 2.4284 2.4301 Young * s / D ensity (xlO ^ im / s) 2 28.30 29.55 28.67 29.17 29.58 30.67 31.0 31.20 CTE xlO-YC 38.1 37.4 36.2 35.7 38.2 35.7 31.9 31.5 Anneal Pt. ° C 710.5 713.0 706.0 705.5 724.5 732.5 743.0 745.0 Strain Pt. ° C 647.5 652.0 648.0 642.5 667.0 667.0 684.5 686.5

IHi Page 14 1230145 V. Description of the invention (π) Table 1 (continued)

Component wt% ^ wt? / 〇 * wt ° / o * wt% * Wf / θ wood SiO, 56.50 55.00 60.50 51.00 55.00 AUO, 15.00 15.00 15.50 15.00 15.00 Β, 〇, 11.00 10.50 10.50 10.50 10.50 Ca〇4.60 6.60 8.60 6.60 4.60 MrO 0.80 0.80 0.80 0.80 0.80 Ba〇0.00 0.00 0.00 0.00 0.00 Sr〇2.00 2.00 2.00 2.00 0.00 La ^ Cs 10.00 10.00 2.00 14.00 14.00 SbA 0.10 0.10 0.10 ——α io 0.10 Totals 100.00 100.00 100.00 100.00 100.00 100.00 Young's Modulus GPa 76.65 79.18 75.47 82.59 79.58 DensityCg / cm3) 2.5644 2.6082 2.4587 2.7099 2.6246 Young's / D ensity (xlO ^ Cm / s) 2 29.89 30.36 30.70 30.48 30.32 CTE xl0-7 ° C 34.0 38.9 36.6 42.1 32.9 Anneal Pt. ° C 733.0 mo 730.5 722.0 mo Strain Pt. ° C 673.5 674.5 663.5 667.0 686.0 ΙΙΙΙΙΙ Page 15 1230145 The diagram is for simple illustration without illustration. ΙΒΙ Page 16

Claims (1)

L--rrrT surround 1. A substrate glass composition for a flat display, the composition includes 55-70 wt% Si02, 10-18 wt% Al2O3, 8-15 wt0 / 〇B2 03, 3-20 wt ° / 〇CaO + SrO + MgO, 1-15 wt% La203. 2. The substrate glass composition according to item 1 of the patent application scope, wherein its La203 may be between 1-10 wt%. 3. The substrate glass composition 'described in item 1 of the scope of the patent application, and the specific Young's modulus of the substrate glass formed thereon is greater than 29.0 x 1 06 (m / s) 2 or more. 4 · The substrate glass composition described in item 1 of the scope of patent application, the specific Young's modulus (specific modulus, s modulus) of the substrate glass formed may be greater than 31 · 0χ 106 (m / s) ^. 5. The substrate glass composition as described in item 1 of the scope of the patent application, the substrate glass formed thereon should have a ^: dot (31: 1 ^ 丨 11? 〇 丨 11 ^ ;, 6111? 61 ^^; 1 ^ 6 ) Above 650 ° C °, 6. If the scope of the patent application, the substrate glass has a strain point of 6 800 ° C. The substrate glass composition described in item 1 can have a strain point temperature higher than 7 · The substrate sloped glass composition as described in the scope of the patent application, which is formed 1230145 VI. The scope of the patent application The substrate glass has an annealing point temperature higher than 700 ° C. 8. The substrate glass composition described in item 1 of the scope of patent application, the substrate glass formed therewith has an annealing point temperature higher than 74 0 ° C 0 9. As described in item 1 of the scope of patent application The substrate glass composition has a thermal expansion coefficient of less than 38 × 10-V ° C. I 0 · The substrate glass composition described in item 1 of the scope of patent application, the substrate glass formed thereon may have a thermal expansion coefficient lower than 3 2x 1 0-7 / ° C. II · The substrate glass composition according to item 1 of the scope of the patent application, the glass substrate composition includes: 60-65wt% Si〇2, 15-16 wt% Al2O3, 10-13 wt% B2O3, 5-10 wt% CaO + SrO + MgO, 1-8 wt% La 20 3〇1 2 · The substrate glass composition as described in item 11 of the scope of patent application, wherein L a 20 is between 1-6 wt scale Good. 1 3 · The specific Young ’s modulus of the substrate glass formed by the substrate glass composition ′ described in item 11 of the scope of patent application may be greater than 30 · 0χ 106 (m / s) ^. 1230145 VI. Application for patent scope 1 4. The substrate glass composition described in item 11 of the scope of patent application, the specific Young's modulus of the substrate glass formed may be greater than 31. Ox 106 (m / s) ^. 15. The substrate glass composition according to item 11 of the scope of patent application, wherein the substrate glass formed has a strain point temperature higher than 6600 ° C. 1 6 · The substrate glass composition described in item 11 of the scope of patent application, the substrate glass formed therewith has a strain point temperature higher than 6 8 0 ° C 〇 1 7 · as in the scope of patent application 丨The substrate glass composition according to item 丨, wherein the formed substrate glass has an annealing point temperature higher than 7 2 0 ° C. 1 8 · The substrate glass composition described in item 丨 丨 of the scope of patent application, the substrate glass formed has an annealing point temperature higher than 7 40 ° C. 1 9 · The substrate glass composition described in item 丨 丨 of the scope of patent application, the substrate glass formed has a thermal expansion coefficient of less than 3 5x 1 0 _7 / ° C. 2 0 · The substrate glass composition as described in item 丨 丨 Page 20 1230145 VI. Scope of patent application --- The thermal expansion coefficient of the substrate glass can be lower than 32x 10-V ° C. 21. The substrate glass composition according to item 11 of the Shengu patent scope, which may be added with a clarifying agent such as 0-1 wt% As2O3 (diarsenic trioxide), 0-1 wt% Sb2O3 (antimony trioxide). 2 2 · The substrate glass composition as described in item 11 of the scope of the patent application, the glass substrate formed can be made by R9 worm process (Over — Fusion Process). I 2 3 · The substrate glass composition as described in item 11 of the scope of the patent application, the glass substrate formed can be made by the SIH-down Draw Process. 2 4. The substrate glass composition according to item 11 of the scope of the patent application, the glass substrate formed can be prepared by a horizontal floating process (F10ating / Tin Bath Process).