Quartz coating process for producing quartz substrates with high infrared reflectivity

Abstract

The present invention discloses a quartz coating process for producing quartz substrates with high infrared reflectivity, belonging to the technical field of quartz substrate coating. The quartz coating process for producing quartz substrates with high infrared reflectivity of the present invention comprises the following steps: Step 1: Cleaning the quartz substrate to remove surface dirt, preparing a vacuum coating device, and evacuating the coating device to a vacuum degree of 8×10 ‑4 ~10×10 ‑4 Pa. The present invention solves the problem of low infrared reflectivity of existing quartz substrates. The quartz coating process for producing quartz substrates with high infrared reflectivity proposed in the present invention uses silicon, nitrogen, silver, and aluminum as coating materials, with an infrared reflectivity of over 90%. Silicon, due to its low melting point, reacts with nitrogen to form silicon nitride, which fuses silver and aluminum particles to form a silicon nitride layer. This ensures reflectivity while improving the strength and chemical stability of the entire film layer.

Description

Technical Field

[0001] The present invention relates to the technical field of quartz substrate coating, in particular to a quartz coating process for producing a quartz substrate with high infrared reflectivity. Background Art

[0002] Quartz is widely used in optical devices, optoelectronic devices, and crystal fields due to its transparency, high refractive index, and low scattering loss.

[0003] Chinese patent publication number CN115341183B discloses a high-precision quartz substrate coating and its production process. The coating is configured as a two-layer structure, consisting of a surface chromium nitride coating and a bottom release composite coating. The quartz substrate processed by this method is protected by the chromium nitride layer during final use. However, when applied to infrared quartz, the quartz substrate suffers from low infrared reflectivity. Summary of the Invention

[0004] The purpose of the present invention is to provide a quartz coating process for producing quartz substrates with high infrared reflectivity. By using silicon, nitrogen, silver and aluminum as coating materials, and silver and aluminum as metal coating materials, the infrared reflectivity is as high as more than 90%, thereby solving the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a quartz coating process for producing a quartz substrate with high infrared reflectivity, comprising the following steps:

[0006] Step 1: Clean the quartz substrate to remove surface dirt, prepare the vacuum coating equipment, and evacuate the coating equipment to a vacuum degree of 8×10 -4 ~10×10 -4 Pa;

[0007] Step 2: Start the coating equipment and heat the quartz substrate at a temperature of 150-200°C for 5-10 minutes. After heating, inject argon into the vacuum chamber for partial pressure control at 0.75 Pa.

[0008] Step 3: Argon is used as the sputtering gas in the coating equipment, silicon is used as the target material, and oxygen is introduced as the reaction gas to form a silicon dioxide film layer on the quartz substrate;

[0009] Step 4: Using argon as the sputtering gas and the silicon nitride film material as the target material, a silicon nitride film layer is deposited on the silicon dioxide film layer by sputtering gas;

[0010] Step 5: After the coating is completed, the substrate and the film surface are annealed at a temperature of 700-800°C, and a step-by-step heating and cooling process is used. After the annealing is completed, the quartz substrate is removed;

[0011] Step 6: Surface treatment of the quartz substrate.

[0012] Preferably, in step three, the argon flow rate is set to 25-35 sccm, the pressure in the equipment is set to 0.4-1.0 Pa, and the ratio of argon to oxygen is 1:3.

[0013] Preferably, the silicon dioxide film layer in step three is formed by four cycles of deposition, and the thickness of the film deposited in a single cycle is 1 μm.

[0014] Preferably, the silicon nitride film layer material includes the following raw materials in parts by weight: 24-28 parts of silicon, 12-18 parts of nitrogen, 7-12 parts of silver, and 2-4 parts of aluminum.

[0015] Preferably, in step 4, the argon flow rate is set to 30-37 sccm, the pressure in the equipment is set to 0.6-0.8 Pa, and the ratio of argon to nitrogen is 4:1.

[0016] Preferably, both step 3 and step 4 are preceded by a pre-sputtering step, wherein the pre-sputtering removes the target oxide film and other non-target substances by ion bombardment.

[0017] Preferably, the silicon nitride film layer in step 4 is divided into two layers, each silicon nitride film layer is formed by four cycles of deposition, and the thickness of the coating in a single cycle is 2 μm.

[0018] Preferably, the step-type heating temperatures during the annealing process are 300°C, 400°C, 500°C, 600°C, 700°C, and 800°C, and are kept warm for 10min, 9min, 8min, 7min, 6min, and 5min, respectively; the step-type cooling temperatures are 700°C, 600°C, 500°C, 400°C, 300°C, 200°C, 150°C, 100°C, and 50°C, and are kept warm for 10min, 10min, 10min, 10min, 10min, 10min, 15min, 15min, and 15min, respectively.

[0019] Preferably, the surface treatment in step six includes the following processes:

[0020] Prepare a lanthanum oxide solution, immerse the cooled quartz substrate in the lanthanum oxide solution, allow it to fully absorb the lanthanum oxide in the solution, take the quartz substrate out of the solution, and dry it to form a lanthanum oxide film on the surface of the quartz substrate.

[0021] Preferably, the lanthanum oxide solution is a solution prepared by mixing lanthanum oxide and ethanol, and the mass ratio of lanthanum oxide to ethanol is 1:3.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] A layer of silicon dioxide film is first coated on the surface of the quartz substrate. Silicon dioxide itself can increase the infrared reflectivity of the quartz substrate. At the same time, silicon dioxide improves the adhesion of the surface of the quartz substrate, providing a good foundation for subsequent coating. On the second layer of film, silicon, nitrogen, silver and aluminum are used as coating materials. Silver and aluminum are used as metal coating materials with an infrared reflectivity of more than 90%. At the same time, taking advantage of the low melting point of silicon, it reacts with nitrogen to generate silicon nitride. Silicon nitride fuses silver and aluminum particles to form a silicon nitride layer, which ensures reflectivity while improving the strength and chemical stability of the entire film layer. Then, a third wrapping film layer is formed by lanthanum oxide, which wraps the outside of the quartz substrate and the coating, improving the firmness of the connection between the coating and the quartz substrate and preventing the coating from falling off. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of the quartz coating process of the present invention. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] To resolve existing issues, see Figure 1 This embodiment provides the following technical solution: a quartz coating process for producing a quartz substrate with high infrared reflectivity, comprising the following steps:

[0027] Step 1: Clean the quartz substrate to remove surface dirt. Wash the quartz substrate with water first, then boil it with 10% NaOH solution for several minutes, then clean it with pure water and ultrasonic wave. Take it out and blow it dry with high-purity nitrogen or bake it in a 100℃ oven for half an hour. Prepare the vacuum coating equipment and evacuate the coating equipment to a vacuum degree of 8×10 -4 ~10×10 - 4 Pa;

[0028] Step 2: Start the coating equipment and heat the quartz substrate at a temperature of 150-200°C for 5-10 minutes. After heating, inject argon into the vacuum chamber for partial pressure control at 0.75 Pa.

[0029] Step 3: Argon is used as the sputtering gas in the coating equipment, silicon is used as the target material, oxygen is introduced as the reaction gas, and a silicon dioxide film layer is formed on the quartz substrate. The argon flow rate is set to 25-35 sccm, the pressure in the equipment is 0.4-1.0 Pa, and the ratio of argon to oxygen is 3:1. The positive ions formed after the ionization of the argon bombard the surface of the target material at high speed, so that the target particles are sputtered out and react with oxygen, and then reach the surface of the substrate to form a silicon dioxide film layer. The silicon dioxide film layer is formed by four cycles of deposition, and the thickness of the single cycle coating is 1 μm;

[0030] Step 4: Using argon as the sputtering gas and silicon nitride film material as the target material, a silicon nitride film is deposited on the silicon dioxide film layer by sputtering gas. The positive ions formed after the argon gas is ionized bombard the target surface at high speed, causing the target silver and aluminum to be sputtered out as silicon particles. The silicon particles have the lowest melting point and react with nitrogen first to form silicon nitride. The silicon nitride, silver and aluminum fuse together to form a mixed film on the silicon dioxide film layer. Silver and aluminum are distributed in the silicon nitride material. The silicon nitride material itself has good reflectivity for infrared rays. With the clamping of silver and aluminum metal materials, the reflectivity is improved. At the same time, silicon nitride can improve the chemical stability and hardness of silver and aluminum. The argon flow rate is set to 30-37 sccm, the pressure in the equipment is 0.6-0.8 Pa, the ratio of argon and nitrogen is 4:1, the silicon nitride film is divided into two layers, each silicon nitride film layer is deposited by four cycles, and the thickness of the single cycle coating is 2 μm.

[0031] The silicon nitride film layer material comprises the following raw materials in parts by weight: 24 to 28 parts of silicon, 12 to 18 parts of nitrogen, 7 to 12 parts of silver and 2 to 4 parts of aluminum;

[0032] Before the formal sputtering, both step 3 and step 4 perform a pre-sputtering step, which removes the target oxide film and other non-target materials by ion bombardment.

[0033] Step five: After the coating is completed, the substrate and the film surface are annealed. The annealing temperature is 700-800℃, and the annealing process adopts step-type heating and step-type cooling. After the annealing is completed, the quartz substrate is taken out. The step-type heating temperatures in the annealing process are 300℃, 400℃, 500℃, 600℃, 700℃, and 800℃, respectively, and they are kept warm for 10min, 9min, 8min, 7min, 6min, and 5min respectively. The step-type cooling temperatures are 700℃, 600℃, 500℃, 400℃, 300℃, 200℃, 150℃, 100℃, and 50℃, respectively, and they are kept warm for 10min, 10min, 10min, 10min, 10min, 10min, 15min, 15min, and 15min respectively. Compared with the method of directly turning off the heating and cooling naturally, the gradient staged cooling has a better aging effect and can significantly improve the firmness of the film.

[0034] Step 6: Surface treatment of the quartz substrate. Surface treatment includes the following processes:

[0035] Prepare a lanthanum oxide solution, immerse the cooled quartz substrate in the lanthanum oxide solution, allow it to fully absorb the lanthanum oxide in the solution, remove the quartz substrate from the solution, and dry it to form a lanthanum oxide film on the surface of the quartz substrate. The lanthanum oxide solution is a solution prepared by mixing lanthanum oxide and ethanol, and the mass ratio of lanthanum oxide to ethanol is 1:3. By adding the lanthanum oxide layer, the anti-fouling and wear resistance of the quartz substrate are improved, and the lanthanum oxide layer wraps the entire quartz substrate and the coating layer to improve the tightness of the coating.

[0036] Example 1:

[0037] The silicon dioxide film layer comprises the following raw materials in parts by weight: 12 parts silicon and 8 parts oxygen;

[0038] The silicon nitride film layer material includes the following raw materials in parts by weight: 24 parts silicon, 12 parts nitrogen, 12 parts silver and 2 parts aluminum;

[0039] The quartz substrate is coated with a film using the above method.

[0040] Example 2:

[0041] The silicon dioxide film layer comprises the following raw materials in parts by weight: 12 parts silicon and 8 parts oxygen;

[0042] The silicon nitride film layer material includes the following raw materials in parts by weight: 30 parts silicon, 12 parts nitrogen, 12 parts silver and 2 parts aluminum;

[0043] The quartz substrate is coated with a film using the above method.

[0044] Example 3:

[0045] The silicon dioxide film layer comprises the following raw materials in parts by weight: 12 parts silicon and 8 parts oxygen;

[0046] The silicon nitride film layer material includes the following raw materials in parts by weight: 24 parts silicon, 12 parts nitrogen, 7 parts silver and 2 parts aluminum;

[0047] The quartz substrate is coated with a film using the above method.

[0048] Comparative Example 1:

[0049] The silicon dioxide film layer comprises the following raw materials in parts by weight: 12 parts silicon and 8 parts oxygen;

[0050] The silicon nitride film material includes the following raw materials in parts by weight: 24 parts silicon, 12 parts nitrogen and 2 parts aluminum;

[0051] The quartz substrate is coated with a film using the above method.

[0052] Comparative Example 2:

[0053] The silicon dioxide film layer comprises the following raw materials in parts by weight: 12 parts silicon and 8 parts oxygen;

[0054] The silicon nitride film layer material includes the following raw materials in parts by weight: 24 parts silicon, 12 parts nitrogen, 7 parts silver and 2 parts aluminum;

[0055] The quartz substrate is coated with a film using the above method, but step six is ​​not performed, and the surface treatment of the quartz substrate is omitted.

[0056] The examples and comparative examples were tested: the film structures of the examples and comparative examples were prepared respectively, and a 10*10 cm film area was randomly selected for testing to observe the coating quality of the cut samples;

[0057]

[0058] As can be seen from the above table, the appearance quality, hardness, reflectivity and film shedding of the films processed in the examples are similar. In Example 3, the amount of silver added is reduced, and the reflectivity of infrared light above 800nm ​​is low. In Comparative Example 1, because no silver is added, the reflectivity of infrared light is low. In the scratch test, a 5×5 grid is scratched on the test film layer by the grid method, and the angle between the cuts is 30-40°. ISO tape is used to firmly stick it to the grid paper. After the tape is torn off, the film layer of Comparative Example 2 falls off. In Comparative Example 2, the lanthanum oxide film is not plated, and the firmness of the film layer is poor.

[0059] In summary, the quartz coating process for producing quartz substrates with high infrared reflectivity proposed in the present invention is as follows: a layer of silicon dioxide film is first coated on the surface of the quartz substrate. Silicon dioxide itself can improve the infrared reflectivity of the quartz substrate. At the same time, silicon dioxide improves the adhesion of the surface layer of the quartz substrate, which provides a good foundation for subsequent coating; on the second layer of film, silicon, nitrogen, silver and aluminum are used as coating materials. Silver and aluminum are used as metal coating materials, and the infrared reflectivity is as high as more than 90%. At the same time, the low melting point of silicon is utilized to react with nitrogen to generate silicon nitride. Silicon nitride fuses silver and aluminum particles to form a silicon nitride layer, which ensures the reflectivity while improving the strength and chemical stability of the entire film layer; then a third wrapping film layer is formed by lanthanum oxide, which wraps the outside of the quartz substrate and the coating, thereby improving the firmness of the connection between the coating and the quartz substrate and preventing the coating from falling off.

[0060] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0061] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A quartz coating process for producing quartz substrates with high infrared reflectivity, characterized in that: The following steps are involved: Step 1: Clean the quartz substrate to remove surface dirt, prepare the vacuum coating equipment, and evacuate the coating equipment to a vacuum degree of 8×10 -4 ~10×10 -4 Pa; Step 2: Start the coating equipment and heat the quartz substrate at a temperature of 150-200°C for 5-10 minutes. After heating, inject argon into the vacuum chamber for partial pressure control at 0.75 Pa. Step 3: Argon is used as the sputtering gas in the coating equipment, silicon is used as the target material, and oxygen is introduced as the reaction gas to form a silicon dioxide film layer on the quartz substrate; Step 4: Using argon as the sputtering gas and the silicon nitride film material as the target material, a silicon nitride film layer is deposited on the silicon dioxide film layer by sputtering gas; Step 5: After the coating is completed, the substrate and the film surface are annealed at a temperature of 700-800°C, and a step-by-step heating and cooling process is used. After the annealing is completed, the quartz substrate is removed; Step 6: Surface treatment of the quartz substrate; The silicon nitride film material comprises the following raw materials in parts by weight: 24-28 parts silicon, 12-18 parts nitrogen, 7-12 parts silver and 2-4 parts aluminum; The surface treatment in step six includes the following processes: Prepare a lanthanum oxide solution, immerse the cooled quartz substrate in the lanthanum oxide solution, allow it to fully absorb the lanthanum oxide in the solution, take the quartz substrate out of the solution, and dry it to form a lanthanum oxide film on the surface of the quartz substrate.

2. The quartz coating process for producing a quartz substrate with high infrared reflectivity according to claim 1, characterized in that: In step 3, the argon flow rate is set to 25-35 sccm, the pressure in the equipment is set to 0.4-1.0 Pa, and the ratio of argon to oxygen is set to 1:

3.

3. The quartz coating process for producing a quartz substrate with high infrared reflectivity according to claim 1, characterized in that: The silicon dioxide film layer in step three is deposited by four cycles, and the thickness of the film deposited in a single cycle is 1 μm.

4. The quartz coating process for producing a quartz substrate with high infrared reflectivity according to claim 1, characterized in that: In step 4, the argon flow rate is set to 30-37 sccm, the pressure in the equipment is set to 0.6-0.8 Pa, and the ratio of argon to nitrogen is set to 4:

1.

5. The quartz coating process for producing a quartz substrate with high infrared reflectivity according to claim 1, characterized in that: Before the formal sputtering, both step 3 and step 4 are subjected to a pre-sputtering step, and the pre-sputtering removes the oxide film of the target material by ion bombardment.

6. The quartz coating process for producing a quartz substrate with high infrared reflectivity according to claim 1, characterized in that: In the fourth step, the silicon nitride film layer is divided into two layers, each silicon nitride film layer is formed by four cycles of deposition, and the thickness of the coating in a single cycle is 2 μm.

7. The quartz coating process for producing a quartz substrate with high infrared reflectivity according to claim 6, characterized in that: During the annealing process, the temperatures of the step-type heating are 300°C, 400°C, 500°C, 600°C, 700°C, and 800°C, and the insulation times are 10 min, 9 min, 8 min, 7 min, 6 min, and 5 min, respectively; the temperatures of the step-type cooling are 700°C, 600°C, 500°C, 400°C, 300°C, 200°C, 150°C, 100°C, and 50°C, and the insulation times are 10 min, 10 min, 10 min, 10 min, 10 min, 15 min, 15 min, and 15 min, respectively.

8. The quartz coating process for producing a quartz substrate with high infrared reflectivity according to claim 7, characterized in that: The lanthanum oxide solution is a solution prepared by mixing lanthanum oxide and ethanol, and the mass ratio of lanthanum oxide to ethanol is 1:3.

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