An efficient method for removing ITO film from optical substrate surface

Abstract

The present invention belongs to the field of optical technology and specifically relates to a highly efficient method for removing ITO thin films from optical substrate surfaces. This method involves roughly evenly sprinkling zinc or aluminum powder onto the surface of the optical substrate coated with the ITO thin film. The ITO thin film surface is then repeatedly and evenly wiped with hydrochloric acid using a soft, corrosion-resistant material. The wiped optical substrate is then placed in a clean water tank and ultrasonically cleaned to remove surface moisture. This method effectively and rapidly removes ITO thin films from optical substrates without significantly damaging the substrate surface. This method is applicable not only to optical materials with good chemical stability, such as K9 glass and quartz glass, but also to easily corroded and damaged optical substrates, such as ZnS, ZnSe, sapphire, CaF2, and BaF2.

Description

Technical Field

[0001] The invention belongs to the field of optical technology, and in particular relates to a method for efficiently removing an ITO film on the surface of an optical substrate. Background Art

[0002] ITO (indium tin oxide) is a composite material with excellent electrical conductivity and light transmittance, making it commonly used in the manufacture of optoelectronic devices. Vacuum coating methods such as magnetron sputtering, ion beam sputtering, radio frequency sputtering, and ion-assisted deposition are commonly used to deposit thin films on optical surfaces that combine excellent electrical conductivity and light transmittance to achieve the desired functionality of optoelectronic devices. However, when the ITO film deposited on the optical substrate fails to meet specifications or exhibits quality issues, it must be removed without damaging the optical substrate surface.

[0003] There are two main types of existing ITO film removal technologies: one is to use physical grinding and polishing to directly remove the ITO film; the other is to immerse the optical device in a chemical solvent such as an acid or alkali, decomposing the ITO film through a chemical reaction, and then thoroughly clean the ITO film through washing. Currently, both of these methods have certain shortcomings. Among them, physical grinding and polishing are inefficient in film removal, and grinding and polishing may damage the surface of the optical substrate and destroy the substrate's surface shape. The chemical solvent immersion method, because the chemical reaction takes a certain amount of time, may corrode the optical substrate and damage the optical surface. This is especially true for substrate materials that are easily corroded by chemical solvents, such as ZnS, ZnSe, sapphire, CaF2, and BaF2. Long immersion times can easily damage the optical substrate. Summary of the Invention

[0004] (1) Technical issues to be resolved

[0005] The technical problem to be solved by the present invention is: in order to improve the removal of ITO film on the surface of optical substrate while not easily damaging the optical substrate, how to propose a method for removing ITO film that is fast, efficient, low-cost, easy to operate, and not easy to damage the optical substrate.

[0006] (2) Technical solution

[0007] In order to solve the above technical problems, the present invention provides a method for efficiently removing the ITO film on the surface of an optical substrate, the method comprising the following steps:

[0008] Step 1: Sprinkle an appropriate amount of metal powder on the surface of the ITO film to be removed;

[0009] Step 2: Use a flexible and acid-resistant tool, dip it in hydrochloric acid, and repeatedly rub the surface of the ITO film sprinkled with metal powder to quickly decompose the ITO film without damaging the surface of the optical substrate;

[0010] Step 3: Use clean water to ultrasonically clean the optical substrate after film removal and dehydrate it.

[0011] Wherein, in step 1, the metal powder is a metal powder material that easily reacts with hydrochloric acid.

[0012] Wherein, in step 1, the metal powder is aluminum powder or zinc powder.

[0013] Wherein, the particles of the aluminum powder or zinc powder are smaller than 0.1 mm.

[0014] The optical substrate includes various acid and alkali corrosion-resistant optical substrates including quartz and K9 glass.

[0015] The optical substrates include various optical substrates that are easily corroded by acids and alkalis and easily damaged, including ZnS, ZnSe, CaF2, BaF2, and sapphire.

[0016] Wherein, in step 2, the flexible and acid-resistant tool is a cotton ball.

[0017] Wherein, in step 2, the flexible and acid-resistant tool is a degreasing cloth.

[0018] Wherein, in the step 2, the time t for wiping the surface of the ITO film with a tool dipped in hydrochloric acid is calculated by t = (S × d) × (5000 ± 1000), in seconds; wherein S is the area of the ITO film, in mm 2 ; d is the geometric thickness of the ITO film, in mm.

[0019] Among them, in the step 3, the optical substrate after removing the ITO film is ultrasonically cleaned in ultrapure water for 3 minutes to 5 minutes; and the optical substrate after ultrasonic cleaning is dehydrated using a volatile organic solvent including anhydrous ethanol, ether, and acetone; or the optical substrate after ultrasonic cleaning is dried in an oven.

[0020] (3) Beneficial effects

[0021] The method provided by the present invention for removing ITO thin films from optical substrate surfaces can effectively and quickly remove ITO thin films coated on optical substrates without damaging the optical substrate surface. This method is applicable not only to optical materials with good chemical stability, such as K9 glass and quartz glass, but also to easily corroded and damaged optical substrates, such as ZnS, ZnSe, sapphire, CaF2, and BaF2.

[0022] Compared with the existing technology, the present invention can quickly remove the ITO film on the surface of the optical substrate without easily damaging the surface of the optical substrate. It is suitable for most optical substrate materials, especially for removing the ITO film plated on the surface of optical substrate materials such as ZnS, ZnSe, sapphire, CaF2, BaF2, which are easily damaged and easily corroded by acid and alkali solutions. The present invention can quickly remove the ITO film without damaging the surface of the optical substrate.

[0023] The zinc powder or aluminum powder used in the technical solution of the present invention has a lower hardness than other particles and is not easy to damage the surface of the optical substrate.

[0024] The zinc powder or aluminum powder used in the technical solution of the present invention reacts with hydrochloric acid, and the heat released causes local heating to promote the reaction of zinc powder or aluminum powder with water to produce OH — ion. OH — The ions react with SnO2 in ITO, and at the same time, the H+ ions in hydrochloric acid react with In2O3 in ITO, which accelerates the decomposition of the ITO film and forms a substance that is easily soluble in water.

[0025] During the wiping process, the fine metal particles have a certain effect of refreshing and removing the small amount of residual impurities on the optical surface, promoting the rapid and complete removal of the ITO film.

[0026] Therefore, the material used in the present invention is simple, the operation is easy, and the ITO film can be completely removed in a short time. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Flowchart of the method for removing ITO film in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, content, and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below with reference to the accompanying drawings and examples.

[0029] In order to solve the above technical problems, the present invention provides a method for efficiently removing the ITO film on the surface of an optical substrate, the method comprising the following steps:

[0030] Step 1: Sprinkle an appropriate amount of metal powder on the surface of the ITO film to be removed;

[0031] Step 2: Use a flexible and acid-resistant tool, dip it in hydrochloric acid, and repeatedly rub the surface of the ITO film sprinkled with metal powder to quickly decompose the ITO film without damaging the surface of the optical substrate. Using hydrochloric acid to wipe the surface of the ITO film sprinkled with metal powder is quick and thorough, without the need for long-term soaking or coating with solvents or pastes, and is therefore less likely to damage the surface of the optical substrate.

[0032] Step 3: Use clean water to ultrasonically clean the optical substrate after film removal and dehydrate it.

[0033] Wherein, in step 1, the metal powder is a metal powder material that easily reacts with hydrochloric acid.

[0034] Wherein, in step 1, the metal powder is aluminum powder or zinc powder.

[0035] The aluminum powder or zinc powder has a particle size of less than 0.1 mm. The aluminum powder or zinc powder sprinkled on the surface of the ITO film can roughly evenly cover the ITO surface.

[0036] The optical substrate includes various acid and alkali corrosion-resistant optical substrates including quartz and K9 glass.

[0037] The optical substrates include various optical substrates that are easily corroded by acids and alkalis and easily damaged, including ZnS, ZnSe, CaF2, BaF2, and sapphire.

[0038] Wherein, in step 2, the flexible and acid-resistant tool is a cotton ball.

[0039] Wherein, in step 2, the flexible and acid-resistant tool is a degreasing cloth.

[0040] Wherein, in the step 2, the time t for wiping the surface of the ITO film with a tool dipped in hydrochloric acid is calculated by t = (S × d) × (5000 ± 1000), in seconds; wherein S is the area of the ITO film, in mm 2 ; d is the geometric thickness of the ITO film, in mm.

[0041] Among them, in the step 3, the optical substrate after removing the ITO film is ultrasonically cleaned in ultrapure water for 3 minutes to 5 minutes; and the optical substrate after ultrasonic cleaning is dehydrated using a volatile organic solvent including anhydrous ethanol, ether, and acetone; or the optical substrate after ultrasonic cleaning is dried in an oven.

[0042] Example 1

[0043] The method for efficiently removing the ITO thin film on the surface of an optical substrate provided in this embodiment includes the following steps:

[0044] Step S110: clear dust and impurities from the surface of the ITO film.

[0045] Preferably, the surface of the optical substrate coated with the ITO film is simply wiped lightly using an absorbent cotton ball dipped in a mixture of anhydrous ethanol and ether.

[0046] Step S120: Sprinkle an appropriate amount of aluminum powder or zinc powder on the surface of the ITO film.

[0047] Preferably, the aluminum powder and zinc powder particles are smaller than 0.1 mm, and the zinc powder can roughly evenly cover the surface of the ITO film.

[0048] Step S130: Use an absorbent cotton ball to pick up hydrochloric acid solution and rub the surface of the ITO film sprinkled with zinc powder repeatedly and evenly.

[0049] Preferably, the concentration of the hydrochloric acid solution used is 10% to 38%.

[0050] Preferably, the time for gently wiping the surface of the ITO film with hydrochloric acid and metal powder is controlled within the range of t = (S × d) × (5000 ± 1000), in seconds; wherein S is the area of the ITO, in mm 2 ; d is the geometric thickness of the ITO film, the unit is converted to mm.

[0051] Preferably, the step of lightly wiping the ITO film with hydrochloric acid and metal powder is performed in a well-ventilated environment.

[0052] Zinc or aluminum powder reacts with hydrochloric acid, releasing heat. This heat generates localized heat, promoting a reaction between the zinc or aluminum powder and water, producing OH- ions. The OH- ions react with the SnO2 in the ITO. Simultaneously, the H+ ions in the hydrochloric acid react with the In2O3 in the ITO, breaking down the ITO film and forming a water-soluble substance. During wiping, the fine metal particles remove any remaining impurities on the optical surface. Simultaneously, the heat released by the reaction between the hydrochloric acid and the aluminum or zinc powder accelerates the decomposition of the ITO film, achieving rapid and complete removal.

[0053] Step S140: placing the lightly wiped optical substrate in an ultrasonic cleaning tank and ultrasonically cleaning it with clean water.

[0054] Preferably, the ultrasonic cleaning time is 3 minutes to 5 minutes.

[0055] Step S150 : Dehydrating the cleaned optical substrate using a volatile solvent such as anhydrous ethanol, ether, or acetone.

[0056] Preferably, an absorbent cotton ball is used to dip into anhydrous ethanol, ether solution or acetone solution and gently wipe the complete surface of the optical substrate to evaporate the moisture on the surface.

[0057] Example 2

[0058] The method of forming an ITO film on the surface of an optical substrate in this embodiment 2 comprises the following steps:

[0059] (1) Use a cotton ball dipped in a mixture of anhydrous ethanol and ether to gently wipe the sapphire optical substrate coated with ITO film on the surface, with an area of about 3000mm 2 , the geometric thickness of ITO film is about 150nm=1.5×10 -5 mm to remove dust and impurities on the surface.

[0060] (2) Sprinkle aluminum powder with particles smaller than 0.1 mm evenly on the surface of the ITO film so that the aluminum powder can roughly cover the surface of the ITO film.

[0061] (3) Use a cotton ball dipped in 20% hydrochloric acid to evenly wipe the surface of the ITO film sprinkled with aluminum powder for about 270 seconds.

[0062] (4) Place the cleaned sapphire optical substrate in an ultrasonic cleaning water tank and use ultrasonic cleaning for 5 minutes.

[0063] (5) Take the cleaned sapphire optical substrate out of the clean water tank and use a cotton ball dipped in a mixture of anhydrous ethanol and ether to gently wipe the surface of the sapphire optical substrate to remove surface moisture.

[0064] (6) When the optical substrate is observed by human eyes under fluorescent light, the surface is clean and free of ITO and other impurities, no obvious damage, and no obvious corrosion marks; the surface resistance of the sapphire substrate is tested by a four-probe square resistance tester, which shows infinite.

[0065] Example 3

[0066] The method of forming an ITO film on the surface of an optical substrate in this embodiment 3 comprises the following steps:

[0067] (1) Use a cotton ball dipped in a mixture of anhydrous ethanol and ether to gently wipe the ZnS optical substrate coated with ITO film on the surface, with an area of about 3000mm 2 , the geometric thickness of ITO film is about 150nm=1.5×10 -5 mm to remove dust and impurities on the surface.

[0068] (2) Sprinkle zinc powder with particles smaller than 0.1 mm evenly on the surface of the ITO film so that the zinc powder can roughly cover the surface of the ITO film.

[0069] (3) Use a degreased cloth dipped in 38% hydrochloric acid to evenly wipe the surface of the ITO film sprinkled with zinc powder for about 180 seconds.

[0070] (4) Place the wiped ZnS optical substrate in an ultrasonic water tank and clean it with ultrasonic waves for 4 minutes.

[0071] (5) Take the cleaned ZnS optical substrate out of the clean water tank and use a cotton ball dipped in acetone to gently wipe the surface of the ZnS substrate to remove moisture from the surface.

[0072] (6) When the ZnS substrate is observed by human eyes under fluorescent light, the surface is clean and free of ITO and other impurities, no obvious damage, and no obvious corrosion marks; the surface resistance of the substrate is tested by a four-probe square resistance tester, which shows infinite.

[0073] Example 4

[0074] The method for forming an ITO film on the surface of an optical substrate of Example 4 comprises the following steps:

[0075] (1) Use a cotton ball dipped in a mixture of anhydrous ethanol and ether to gently wipe the quartz optical substrate coated with ITO film on the surface, with an area of about 3000mm 2 , the geometric thickness of ITO film is about 150nm=1.5×10 -5 mm to remove dust and impurities on the surface.

[0076] (2) Sprinkle aluminum powder with particles smaller than 0.1 mm evenly on the surface of the ITO film so that the zinc powder can roughly cover the surface of the ITO film.

[0077] (3) Use a degreased cloth dipped in 10% hydrochloric acid to evenly wipe the surface of the ITO film sprinkled with aluminum powder for about 220 seconds.

[0078] (4) Place the wiped quartz substrate in an ultrasonic cleaning water tank and clean it with ultrasonic waves for 3 minutes.

[0079] (5) Take the cleaned quartz substrate out of the clean water tank and use a cotton ball dipped in a mixture of anhydrous ethanol and ether to gently wipe the surface of the quartz substrate to remove moisture from the surface.

[0080] (6) When the quartz substrate is observed by human eyes under fluorescent light, the surface is clean and free of ITO and other impurities, no obvious damage, and no obvious corrosion marks; the surface resistance of the substrate is tested by a four-probe square resistance tester, which shows infinite.

[0081] In summary, the present invention belongs to the field of optical technology, specifically relating to a highly efficient method for removing ITO thin films from optical substrate surfaces. This method utilizes zinc or aluminum powder and hydrochloric acid to act on the ITO film surface. This method, through a short period of wiping and cleaning, is not susceptible to damage to various optical substrates, including easily corroded optical substrates such as ZnS, ZnSe, CaF2, BaF2, and sapphire, while exhibiting high cleaning efficiency. The process includes: removing dust and impurities from the surface of the optical substrate coated with the ITO film, and roughly evenly sprinkling zinc or aluminum powder with particles smaller than 0.1 mm on the surface of the ITO film; then repeatedly and evenly wiping the surface of the ITO film with hydrochloric acid at a concentration of 10% to 38% using a soft, corrosion-resistant material, such as a cotton ball or cloth. The wiping duration is controlled within t = (S × d) × (5000 ± 1000) seconds, where S is the area of the ITO film in mm2, and d is the geometric thickness of the ITO film in mm. Then place the wiped optical substrate in a clean water tank and clean it ultrasonically for 3 to 5 minutes. Take out the optical substrate and wipe the surface with a volatile organic solvent such as anhydrous ethanol, ether mixture or acetone to remove surface moisture.

[0082] When wiping the surface of an optical substrate dusted with zinc or aluminum powder with cotton wool or cotton cloth dipped in hydrochloric acid, the hydrochloric acid and the zinc or aluminum powder react chemically, releasing heat. This heat generates localized heat, promoting a reaction between the zinc or aluminum powder and water, producing OH- ions. The OH- ions react with the SnO2 in the ITO. Simultaneously, the H+ ions in the hydrochloric acid react with the In2O3 in the ITO, decomposing the ITO film and forming a water-soluble substance. While wiping, the fine metal particles can refresh and remove small amounts of residual impurities on the optical surface. Simultaneously, the heat released by the reaction between the hydrochloric acid and the aluminum or zinc powder promotes the decomposition of the ITO film, achieving efficient removal of the ITO film.

[0083] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for efficiently removing an ITO film from an optical substrate surface, characterized in that: The method comprises the following steps: Step 1: Sprinkle an appropriate amount of metal powder on the surface of the ITO film to be removed; Step 2: Use a flexible and acid-resistant tool, dip it in hydrochloric acid, and repeatedly rub the surface of the ITO film sprinkled with metal powder to quickly decompose the ITO film without damaging the surface of the optical substrate; Step 3: Use clean water ultrasonic cleaning to clean the optical substrate after film removal and perform dehydration treatment; Wherein, in step 1, the metal powder is a metal powder material that easily reacts with hydrochloric acid.

2. The method for efficiently removing the ITO film from the optical substrate surface as claimed in claim 1, wherein: In step 1, the metal powder is aluminum powder or zinc powder.

3. The efficient removal method of ITO film on optical substrate surface as claimed in claim 2, wherein: The particles of the aluminum powder or zinc powder are smaller than 0.1 mm.

4. The method for efficiently removing the ITO film from the optical substrate surface as claimed in claim 1, wherein: The optical substrate includes various acid and alkali corrosion-resistant optical substrates including quartz and K9 glass.

5. The efficient removal method of ITO film on optical substrate surface as claimed in claim 1, characterized in that: The optical substrates include various optical substrates that are easily corroded by acids and alkalis and easily damaged, including ZnS, ZnSe, CaF2, BaF2, and sapphire.

6. The method for efficiently removing the ITO film from the surface of an optical substrate as claimed in claim 1, wherein: In step 2, the flexible and acid-resistant tool is a cotton ball.

7. The efficient removal method of ITO film on optical substrate surface as claimed in claim 1, characterized in that: In step 2, the flexible and acid-resistant tool is a degreasing cloth.

8. The efficient removal method of ITO film on optical substrate surface as claimed in claim 1, characterized in that: In step 2, the time t for wiping the surface of the ITO film with a tool dipped in hydrochloric acid is calculated by t = (S × d) × (5000 ± 1000), in seconds; where S is the area of the ITO film, in mm 2 ; d is the geometric thickness of the ITO film, in mm.

9. The method for efficiently removing the ITO film from the optical substrate surface as claimed in claim 1, wherein: In the step 3, the optical substrate after the ITO film is removed is ultrasonically cleaned in ultrapure water for 3 minutes to 5 minutes; and the optical substrate after ultrasonic cleaning is dehydrated using a volatile organic solvent including anhydrous ethanol, ether, and acetone; or the optical substrate after ultrasonic cleaning is dried in an oven.

Images