Method for preventing metal oxide from being separated out from surface of alkali-free glass substrate

Abstract

The invention discloses a method for preventing metal oxide from being separated out from the surface of an alkali-free glass substrate, and belongs to the technical field of glass. According to the technical scheme, when annealing of a TFT alkali-free glass substrate is completed, plasma bombardment treatment is carried out on the surface of the TFT alkali-free glass substrate; wherein the plasma is argon and hydrogen in a volume ratio of (4-9): 1, or argon, hydrogen and nitrogen in a volume ratio of (3-6): 1: 1, or argon, hydrogen, helium and nitrogen in a volume ratio of (6-8): (1-3): (0.3-1.7): (0.3-1.7), or argon, hydrogen and helium in a volume ratio of (6-8): (1-3): (1-1.7). According to the method, the problem that metal oxides are separated out from the surface of the TFT alkali-free glass substrate after the TFT alkali-free glass substrate is stored for a long time is practically solved by precisely adjusting the gas composition, proportion and concentration of the plasma, and a foundation is laid for high-quality development of the panel display industry.

Description

Technical Field

[0001] The invention relates to the technical field of glass, and in particular to a method for preventing metal oxides from precipitating on the surface of an alkali-free glass substrate. Background Art

[0002] As a key basic material for flat panel display devices such as liquid crystal display and organic light-emitting diode display, the quality of TFT alkali-free glass substrate plays a vital role in downstream processes and product performance. In the actual production and storage process, it is found that when the TFT alkali-free glass substrate is stored for a long time, the trace metal impurities inside the glass will gradually migrate to the surface and precipitate metal oxides. These precipitated metal oxides will change the physical and chemical properties of the surface of the glass substrate, such as increasing the surface roughness, changing the surface charge distribution, etc., and then cause many problems in the subsequent downstream processes such as photolithography, coating, and etching. In the photolithography process, metal oxide particles may cause uneven coating of photoresist, affect the pattern resolution, and make the size deviation of the manufactured transistor exceed the allowable range; in the coating process, metal oxides will affect the adhesion of the film layer, easily cause the film layer to fall off, and reduce the reliability of the display device; in the etching process, the uneven distribution of metal oxides will cause inconsistent etching rates, and ultimately cause defects such as uneven display, bright spots and dark spots of the display panel, which seriously affects the product yield and increases production costs.

[0003] Therefore, how to prevent the precipitation of metal oxides on the surface of the alkali-free glass substrate during storage is an urgent problem to be solved. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for preventing metal oxides from precipitating on the surface of an alkali-free glass substrate, so as to ensure smooth progress of downstream processes and improve the quality and yield of display products.

[0005] The technical solution of the present invention is:

[0006] The method for preventing metal oxide from precipitating on the surface of an alkali-free glass substrate comprises: when the TFT alkali-free glass substrate has been annealed and the metal impurities on the surface have not yet migrated in large quantities, the surface is subjected to plasma bombardment treatment; wherein the plasma is composed of specific gases and is excited in a low-pressure environment to generate high-energy particles to bombard the surface of the glass substrate, the plasma is argon and hydrogen in a volume ratio of (4-9):1, which can ensure that a sufficient number of high-energy argon particles are used to bombard the surface of the glass substrate to remove crystal nuclei and that an appropriate amount of active hydrogen atoms are available to react with metal impurities; or argon, hydrogen and nitrogen in a volume ratio of (3-6):1:1, wherein the introduction of nitrogen can further stabilize the plasma environment and help improve the uniformity of the treatment; or argon, hydrogen, helium and nitrogen in a volume ratio of (6-8):(1-3):(0.3-1.7):(0.3-1.7), or argon, hydrogen and helium in a volume ratio of (6-8):(1-3):(1-1.7).

[0007] On the one hand, high-energy particles can remove extremely tiny metal oxide nuclei already on the glass surface, preventing them from growing further; on the other hand, the active hydrogen atoms in the plasma can chemically react with metal impurity atoms in the shallow layer of the surface, converting them into more stable metal hydride forms that are less likely to migrate and precipitate, thereby reducing the possibility of subsequent metal oxide precipitation from the source.

[0008] Preferably, the particle concentration of the plasma is 2×10 12 -5×10 12 Pieces / cm 3 This concentration range can achieve the best treatment effect. It will not cause insufficient treatment due to too low plasma particle concentration, nor will it cause unnecessary damage to the surface of the glass substrate due to too high concentration.

[0009] Preferably, when the plasma is a mixed gas of argon and hydrogen in a volume ratio of 7:1, the particle concentration of the plasma is 3×10 12 Pieces / cm 3 , the processing time is 10min.

[0010] Preferably, when the plasma is a mixed gas of argon, hydrogen and nitrogen in a volume ratio of 5:1:1, the particle concentration of the plasma is 4×10 12 Pieces / cm 3 , the processing time is 15min.

[0011] Preferably, when the plasma is a mixed gas of argon, hydrogen, helium and nitrogen in a volume ratio of 7:2:0.5:0.5, the particle concentration of the plasma is 3×10 12 Pieces / cm 3 , the processing time is 12min.

[0012] Preferably, when the plasma is a mixed gas of argon, hydrogen and helium in a volume ratio of 8:1:1, the particle concentration of the plasma is 2.5×10 12 Pieces / cm 3 , the processing time is 9 minutes.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The method of the present invention uses a plasma composed of a specific gas to pre-treat the surface of the TFT alkali-free glass substrate when the substrate has just been produced and the metal impurities on the surface have not yet migrated in large quantities, thereby reducing the possibility of subsequent metal oxide precipitation from the source, thereby effectively inhibiting the precipitation of metal oxides on the TFT alkali-free glass substrate.

[0015] 2. The present invention can ensure the smooth progress of downstream processes: reduce the uneven coating of photoresist caused by metal oxide particles, control the size deviation of the manufactured transistor within the allowable range, and improve the pattern resolution; avoid the metal oxide from affecting the adhesion of the film layer, prevent the film layer from falling off, enhance the adhesion of the film layer, and ensure the quality of the coating; improve the problem of inconsistent etching rate caused by uneven distribution of metal oxides, and reduce the display unevenness, bright spots and dark spots of the display panel. In addition, the present invention greatly prolongs the storage time of TFT alkali-free glass substrate products.

[0016] 3. The present invention effectively solves the problem of metal oxide precipitation on the surface of TFT alkali-free glass substrate after long-term storage by precisely adjusting the gas composition, proportion and concentration of plasma, laying the foundation for the high-quality development of the flat panel display industry. DETAILED DESCRIPTION

[0017] In order to enable persons skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0018] Example 1

[0019] In the method of preventing metal oxides from precipitating on the surface of the alkali-free glass substrate of the present embodiment, after the annealing of the TFT alkali-free glass substrate is completed, the surface is subjected to plasma bombardment treatment, specifically: a mixed gas of argon and hydrogen with a volume ratio of 7:3 is used to generate plasma, the TFT alkali-free glass substrate is placed in a radio frequency plasma treatment device, and the plasma particle concentration is adjusted to 3×10 12 Pieces / cm 3 The processing time is 10 minutes, and the glass substrate is stored normally after the processing.

[0020] After 6 months of storage, elemental analysis was performed on the surface of the glass substrate using an X-ray photoelectron spectrometer (XPS), and it was detected that the amount of metal oxide precipitation on the surface of the glass substrate was reduced by about 98.6% compared with the amount of metal oxide precipitation on the surface of the untreated glass substrate.

[0021] Example 2

[0022] In the method of this embodiment for preventing metal oxides from precipitating on the surface of the alkali-free glass substrate, after the annealing of the TFT alkali-free glass substrate is completed, the surface is subjected to plasma bombardment treatment, specifically: a mixed gas of argon, hydrogen and nitrogen with a volume ratio of 5:1:1 is used to generate plasma, the TFT alkali-free glass substrate is placed in a radio frequency plasma treatment device, and the plasma particle concentration is adjusted to 4×10 12 Pieces / cm 3 The processing time is 15 minutes, and the glass substrate is stored normally after processing.

[0023] After 6 months of storage, elemental analysis was performed on the surface of the glass substrate using an X-ray photoelectron spectrometer (XPS), and it was detected that the amount of metal oxide precipitation on the surface of the glass substrate was reduced by about 96.5% compared with the amount of metal oxide precipitation on the surface of the untreated glass substrate.

[0024] Example 3

[0025] In the method of preventing metal oxides from precipitating on the surface of the alkali-free glass substrate of the present embodiment, after the annealing of the TFT alkali-free glass substrate is completed, the surface is subjected to plasma bombardment treatment, specifically: a mixed gas of argon, hydrogen, helium and nitrogen with a volume ratio of 7:2:0.5:0.5 is used to generate plasma, the TFT alkali-free glass substrate is placed in a radio frequency plasma treatment device, and the plasma particle concentration is adjusted to 3×10 12 Pieces / cm 3 The processing time is 12 minutes, and the glass substrate is stored normally after processing.

[0026] After 6 months of storage, elemental analysis was performed on the surface of the glass substrate using an X-ray photoelectron spectrometer (XPS), and it was detected that the amount of metal oxide precipitation on the surface of the glass substrate was reduced by about 97.7% compared with the amount of metal oxide precipitation on the surface of the untreated glass substrate.

[0027] Example 4

[0028] In the method of preventing metal oxides from precipitating on the surface of the alkali-free glass substrate of the present embodiment, after the annealing of the TFT alkali-free glass substrate is completed, the surface is subjected to plasma bombardment treatment, specifically: a mixed gas of argon, hydrogen and helium with a volume ratio of 8:1:1 is used to generate plasma, the TFT alkali-free glass substrate is placed in a radio frequency plasma treatment device, and the plasma particle concentration is adjusted to 2.5×10 12 Pieces / cm 3 The processing time is 9 minutes, and the glass substrate is stored normally after processing.

[0029] After 6 months of storage, elemental analysis was performed on the surface of the glass substrate using an X-ray photoelectron spectrometer (XPS), and it was detected that the amount of metal oxide precipitation on the surface of the glass substrate was reduced by about 93.2% compared with the amount of metal oxide precipitation on the surface of the untreated glass substrate.

[0030] Comparative Example 1

[0031] The method for preventing metal oxides from precipitating on the surface of the alkali-free glass substrate in Comparative Example 1 is to perform plasma bombardment treatment on the surface of the TFT alkali-free glass substrate after annealing, specifically, to generate plasma using pure argon gas, place the TFT alkali-free glass substrate in a radio frequency plasma treatment device, and adjust the plasma particle concentration to 3×10 12 Pieces / cm 3 The processing time is 10 minutes, and the glass substrate is stored normally after the processing.

[0032] After 6 months of storage, elemental analysis of the glass substrate surface was performed using an X-ray photoelectron spectrometer (XPS), and it was detected that the amount of metal oxide precipitation on the glass substrate surface was almost the same as that on the untreated glass substrate surface.

[0033] Comparative Example 2

[0034] The method for preventing metal oxides from precipitating on the surface of the alkali-free glass substrate in comparative example 2 is to perform plasma bombardment treatment on the surface of the TFT alkali-free glass substrate after annealing, specifically: using a mixed gas of argon and hydrogen with a volume ratio of 2:8 to generate plasma, placing the TFT alkali-free glass substrate in a radio frequency plasma treatment device, and adjusting the plasma particle concentration to 3×10 12 Pieces / cm 3 The processing time is 10 minutes, and the glass substrate is stored normally after the processing.

[0035] After 6 months of storage, the surface of the glass substrate was analyzed by X-ray photoelectron spectrometer (XPS), and the amount of metal oxide precipitation on the surface of the glass substrate was detected to be about 40% lower than that on the surface of the untreated glass substrate. However, due to the high proportion of hydrogen in the plasma, bubbling was found in the film layer during the subsequent coating process. This is because too many active hydrogen atoms react with metal impurities, changing the microstructure of the surface of the glass substrate, resulting in unstable film adhesion and a decrease in product yield.

[0036] Comparative Example 3

[0037] The method for preventing metal oxides from precipitating on the surface of the alkali-free glass substrate of Comparative Example 3 is to perform plasma bombardment treatment on the surface of the TFT alkali-free glass substrate after annealing, specifically: using a mixed gas of argon, hydrogen and nitrogen with a volume ratio of 5:1:1 to generate plasma, placing the TFT alkali-free glass substrate in a radio frequency plasma treatment device, and adjusting the plasma particle concentration to 8×10 12 Pieces / cm 3 The processing time is 8 minutes, and the glass substrate is stored normally after processing.

[0038] After 6 months of storage, the surface of the glass substrate was analyzed by X-ray photoelectron spectrometer (XPS), and the amount of metal oxide precipitation on the surface of the glass substrate was detected to be about 50% lower than that of the untreated glass substrate. However, due to the high concentration of plasma particles, the surface of the glass substrate was damaged to a certain extent. In the subsequent etching process, the problem of uneven etching rate was aggravated, and the display unevenness of the display panel was more serious than that of the untreated glass substrate.

[0039] Comparative Example 4

[0040] The method for preventing metal oxides from precipitating on the surface of the alkali-free glass substrate of Comparative Example 4 is to perform plasma bombardment treatment on the surface of the TFT alkali-free glass substrate after the annealing is completed and the substrate is stored for 3 months. Specifically, a mixed gas of argon and hydrogen with a volume ratio of 7:3 is used to generate plasma, and the TFT alkali-free glass substrate is placed in a radio frequency plasma treatment device, and the plasma particle concentration is adjusted to 3×10 12 Pieces / cm 3 The processing time is 10 minutes, and the glass substrate is stored normally after the processing.

[0041] After 6 months of storage, the surface of the glass substrate was analyzed by X-ray photoelectron spectrometer (XPS), and it was detected that the amount of metal oxide precipitation on the surface of the glass substrate was reduced by about 37% compared with the amount of metal oxide precipitation on the surface of the untreated glass substrate. Compared with Example 1, the amount of metal oxide precipitation on the surface of the glass substrate of Comparative Example 4 is relatively large. This is because the glass substrate is treated with plasma after a large amount of metal impurities migrate, and at this time, some metal impurities have formed large particles or aggregates on the surface. It is difficult for plasma treatment to completely remove or transform these impurities, resulting in poor precipitation inhibition effect.

[0042] Comparative Example 5

[0043] The method for preventing metal oxides from precipitating on the surface of the alkali-free glass substrate in Comparative Example 5 is to perform plasma bombardment treatment on the surface of the TFT alkali-free glass substrate after annealing, specifically: using pure hydrogen mixed gas to generate plasma, placing the TFT alkali-free glass substrate in a radio frequency plasma treatment device, and adjusting the plasma particle concentration to 3×10 12 Pieces / cm 3 The processing time is 10 minutes, and the glass substrate is stored normally after the processing.

[0044] After 6 months of storage, the surface of the glass substrate was analyzed by X-ray photoelectron spectrometer (XPS), and the amount of metal oxide precipitation on the surface of the glass substrate was detected to be about 63% lower than that of the untreated glass substrate. However, due to the use of pure hydrogen plasma, there is a lack of high-energy argon particles and other effects on the removal of crystal nuclei, and the treatment effect is limited by the reaction of active hydrogen atoms with metal impurities. At the same time, pure hydrogen plasma may cause a certain degree of damage to the silicon-oxygen network structure on the surface of the glass substrate, reduce the stability of the glass surface, and further affect the overall performance of the glass substrate. In the subsequent process, more problems may be caused, such as the increase of surface microcracks, which is not conducive to the long-term use and reliability of the product.

[0045] It can be seen from the above embodiments and comparative examples that the method for preventing the precipitation of metal oxides on the surface of an alkali-free glass substrate of the present invention can effectively inhibit the precipitation of surface metal oxides on a TFT alkali-free glass substrate according to the precise adjustment of different gas compositions, proportions and plasma particle concentrations, thereby providing a reliable substrate quality guarantee for the downstream flat panel display device manufacturing process. However, unreasonable gas ratios and plasma particle concentrations will lead to many problems, affecting product quality and yield.

Claims

1. A method for preventing metal oxide from precipitating on the surface of an alkali-free glass substrate, characterized in that: When the TFT alkali-free glass substrate is annealed, its surface is subjected to plasma bombardment treatment; wherein the plasma is argon and hydrogen in a volume ratio of (4-9):1, or argon, hydrogen and nitrogen in a volume ratio of (3-6):1:1, or argon, hydrogen, helium and nitrogen in a volume ratio of (6-8):(1-3):(0.3-1.7):(0.3-1.7), or argon, hydrogen and helium in a volume ratio of (6-8):(1-3):(1-1.7).

2. The method for preventing metal oxide from precipitating on the surface of an alkali-free glass substrate according to claim 1, wherein: The particle concentration of the plasma is 2×10 12 -5×10 12 Pieces / cm 3 .

3. The method for preventing metal oxide from precipitating on the surface of an alkali-free glass substrate according to claim 2, wherein: When the plasma is a mixed gas of argon and hydrogen with a volume ratio of 7:1, the particle concentration of the plasma is 3×10 12 Pieces / cm 3 , the processing time is 10min.

4. The method for preventing metal oxide from precipitating on the surface of an alkali-free glass substrate according to claim 2, wherein: When the plasma is a mixed gas of argon, hydrogen and nitrogen in a volume ratio of 5:1:1, the particle concentration of the plasma is 4×10 12 Pieces / cm 3 , the processing time is 15min.

5. The method for preventing metal oxide from precipitating on the surface of an alkali-free glass substrate according to claim 2, wherein: When the plasma is a mixed gas of argon, hydrogen, helium and nitrogen in a volume ratio of 7:2:0.5:0.5, the particle concentration of the plasma is 3×10 12 Pieces / cm 3 , the processing time is 12min.

6. The method for preventing metal oxide from precipitating on the surface of an alkali-free glass substrate according to claim 2, wherein: When the plasma is a mixed gas of argon, hydrogen and helium in a volume ratio of 8:1:1, the particle concentration of the plasma is 2.5×10 12 Pieces / cm 3 , the processing time is 9 minutes.