Electrostatic spray method for insulating thin film on surface of quartz boat

Abstract

The application discloses a kind of electrostatic spraying method of quartz boat surface insulating film, belong to the field of quartz boat, comprising the following steps: S1, by electrostatic induction and make the surface of quartz boat pre-charged;S2, using electrostatic spraying gun on quartz boat electrostatic spraying polymer coating, obtain surface insulating film;Wherein, in surface insulating film, the ratio of the total thickness of groove top surface film layer of quartz boat and the total thickness of groove bottom surface film layer is 1~3.The application improves the spraying difference ratio of the top surface and the bottom surface of the groove of quartz boat.

Description

Technical Field

[0001] This invention relates to the field of quartz boats, and more specifically, to an electrostatic spraying method for applying an insulating film to the surface of a quartz boat. Background Technology

[0002] A quartz boat is a special instrument made of high-purity quartz glass. It typically has a boat-like or rack-like shape with precise grooves. Due to its ability to withstand extremely high temperatures, its high purity, and its non-conductive properties, quartz boats are used as "transport trays" and "reaction containers" in semiconductor manufacturing processes. They safely carry and transport silicon wafers to complete critical processes such as wet etching. They isolate current and impurities, preventing interference with the process precision of the silicon wafers inside the boat, and eliminating metal contamination to ensure chip purity. In the semiconductor wet etching process, the wafers need to be immersed in highly corrosive chemical reagents to remove surface materials. During this process, the quartz boat holding the wafers faces harsh conditions, therefore surface treatment is required to achieve corrosion resistance.

[0003] In certain extreme environments of semiconductor processes, the properties of the quartz boat material itself are insufficient to prevent corrosion and eliminate metal contamination to ensure chip purity. Therefore, a protective layer must be added as a "double insurance" to ensure the absolute purity and stability of the process.

[0004] Compared with traditional air spraying or brushing, electrostatic spraying has the advantages of being more efficient, more uniform, more economical, and more environmentally friendly because it can make the paint penetrate deeper more easily by using electric field force. Therefore, it is widely used in electronics, shipbuilding, aerospace and other fields.

[0005] Due to the unique nature of the material (quartz boats are made of non-conductive materials) and structure (grooves are distributed on the quartz boats), it is quite difficult to add a protective layer by forming a polymer coating on the quartz boat through electrostatic spraying.

[0006] The existing method of adding a protective layer by electrostatic spraying polymer coating on quartz boats is to directly spray the polymer coating onto the quartz boat. However, this method suffers from low powder application efficiency in the grooves of the quartz boat, resulting in a large difference between the coating on the top and bottom surfaces of the grooves.

[0007] The above background information is provided to facilitate understanding of the present invention and is not intended to be publicly known technology disclosed to the general public prior to the application of this invention. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides an electrostatic spraying method for an insulating film on the surface of a quartz boat, which improves the spraying difference ratio between the top and bottom surfaces of the grooves in the quartz boat.

[0009] An electrostatic spraying method for an insulating film on the surface of a quartz boat includes the following steps: S1, pre-charging the surface of the quartz boat by electrostatic induction; S2, using an electrostatic spray gun to electrostatically spray polymer coating onto a quartz boat to obtain a surface insulating film; Among them, in the surface insulating film, the ratio of the total thickness of the top surface film layer of the quartz boat to the total thickness of the bottom surface film layer of the groove is 1 to 3.

[0010] Optionally, before S1, there is also S0, in which a layer of primer without conductive particles is sprayed onto the surface of the quartz boat by air spraying to form a primer film without conductive particles.

[0011] Optionally, in S0, the sprayed primer is pre-cured to form the primer film without conductive particles, and the thickness of the primer film without conductive particles is 15 micrometers to 25 micrometers.

[0012] Optionally, in S0, pre-curing is carried out at 35℃~60℃.

[0013] Optionally, in S2, electrostatic spraying includes the following steps: S21, uses electrostatic spraying guns to electrostatically spray polymer coatings onto quartz boats; S22, melt-forming film; S23, repeat S21~S22 until the coating thickness reaches the set target thickness.

[0014] Optionally, in S2, the parameters for electrostatic spraying are: electrostatic spraying voltage of 60 kV, electrostatic spraying current of 20 μA, and single electrostatic spraying time of 20 seconds.

[0015] Optionally, the polymer coating is one of epoxy resin coating, polyurethane coating, acrylic resin coating, and silicone coating, and the primer without conductive particles is one of epoxy resin insulating primer, polyurethane insulating primer, acrylic insulating primer, and silicone insulating primer.

[0016] Optionally, the dimensions of the quartz boat are 600mm×400mm×400mm, and the dimensions of the groove of the quartz boat are 3mm in length, 2mm in width, and 6mm in depth.

[0017] Optionally, in S1, the electrostatic generator is pre-charged with a voltage of 20 kV.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention reduces the ratio of the total thickness of the film layer on the top and bottom surfaces of the groove to below 3 by pre-charging.

[0019] The present invention further reduces the ratio of the total thickness of the film layer on the top and bottom surfaces of the groove to below 2 by forming a primer film without conductive particles on the quartz boat before pre-charging, which preserves the surface charge for a longer period of time during subsequent pre-charging. Detailed Implementation

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection via an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] The technical solution of the present invention will be described in detail below with specific embodiments; the following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0023] An electrostatic spraying method for applying an insulating film to the surface of a quartz boat includes the following steps: S1, the quartz boat is placed between the discharge needle of the electrostatic generator and the grounded metal plate, and the position of the discharge needle is continuously moved according to the shape of the substrate, so that the surface of the quartz boat is pre-charged by electrostatic induction. S2, using an electrostatic spray gun to electrostatically spray polymer coating onto a quartz boat to obtain a surface insulating film; Among them, in the surface insulating film, the ratio of the total thickness of the top surface film layer of the quartz boat to the total thickness of the bottom surface film layer of the groove is 1 to 3.

[0024] In one or another specific embodiment of the present invention, in order to further reduce the ratio of the total thickness of the top surface film layer to the total thickness of the bottom surface film layer of the quartz boat, before S1, S0 is included, in which a layer of primer without conductive particles is sprayed onto the surface of the quartz boat by air spraying to form a primer film without conductive particles.

[0025] In one or another specific embodiment of the present invention, in S0, the sprayed primer is pre-cured to form the primer film without conductive particles, and the thickness of the primer film without conductive particles is 15 micrometers to 25 micrometers.

[0026] In one or another specific embodiment of the present invention, in S0, pre-curing is carried out at 35°C to 60°C.

[0027] In one or another embodiment of the present invention, S2, electrostatic spraying includes the following steps: S21, uses electrostatic spraying guns to electrostatically spray polymer coatings onto quartz boats; S22, melt-forming film; S23, repeat S21~S22 until the coating thickness reaches the set target thickness.

[0028] In one or another specific embodiment of the present invention, the polymer coating is one of epoxy resin coating, polyurethane coating, acrylic resin coating, and silicone coating, and the primer without conductive particles is one of epoxy resin insulating primer, polyurethane insulating primer, acrylic insulating primer, and silicone insulating primer.

[0029] Example 1 In this embodiment, the dimensions of the quartz boat are 600mm×400mm×400mm, and the dimensions of the groove are 3mm in length, 2mm in width, and 6mm in depth.

[0030] An electrostatic spraying method for applying an insulating film to the surface of a quartz boat includes the following steps: S1, the quartz boat is placed between the discharge needle of the electrostatic generator and the grounded metal plate, and the position of the discharge needle is continuously moved according to the shape of the substrate. The surface of the quartz boat is pre-charged by electrostatic induction. The electrostatic generator is pre-charged with a voltage of 20 kV.

[0031] S2, a polymer coating is formed on a quartz boat by electrostatic spraying using an electrostatic spray gun. The electrostatic spraying parameters are shown in Table 1.

[0032] This step includes the following steps: S21, using an electrostatic spray gun to electrostatically spray polymer coatings onto a quartz boat.

[0033] S22, high-temperature melting to form a film.

[0034] S23, repeat S21~S22 until the coating thickness reaches 300 micrometers.

[0035] The thickness of the top and bottom film layers of the groove was measured, and the results are shown in Table 2 below.

[0036] Comparative Example 1 The only difference between this comparative example and Example 1 is that: This comparative example does not include S1, meaning the quartz boat is not pre-charged.

[0037] The thickness of the top and bottom film layers of the groove was measured, and the results are shown in Table 2 below.

[0038] Example 2 In this embodiment, the dimensions of the quartz boat are 600mm×400mm×400mm, and the dimensions of the groove are 3mm in length, 2mm in width, and 6mm in depth.

[0039] An electrostatic spraying method for applying an insulating film to the surface of a quartz boat includes the following steps: S0, a primer without conductive particles is sprayed onto the surface of the quartz boat by air spraying, and pre-cured at 50°C to form a primer film without conductive particles with a thickness of 20 micrometers.

[0040] S1, the quartz boat with the primer film without conductive particles from S0 is placed between the discharge needle of the electrostatic generator and the grounded metal plate, and the position of the discharge needle is continuously moved according to the shape of the substrate. The surface of the quartz boat with the primer film without conductive particles is pre-charged by electrostatic induction. The pre-charge voltage of the electrostatic generator is 20 kV.

[0041] S2, a polymer coating is formed by electrostatic spraying on a quartz boat with a primer film containing non-conductive particles using an electrostatic spray gun. The electrostatic spraying parameters are shown in Table 1.

[0042] This step includes the following steps: S21, using an electrostatic spray gun to electrostatically spray polymer coatings onto a quartz boat with a primer film containing non-conductive particles.

[0043] S22, high-temperature melting to form a film.

[0044] S23, repeat S21~S22 until the coating thickness reaches 300μm.

[0045] The thickness of the top and bottom film layers of the groove was measured, and the results are shown in Table 2 below.

[0046] In this embodiment, the primer film without conductive particles provides a dielectric layer to retain surface charge for a longer period of time.

[0047] Comparative Example 2 The only difference between this comparative example and Example 2 is that: In this comparative example, S1 is not included, that is, the quartz boat with a primer film containing no conductive particles is not pre-charged.

[0048] The thickness of the top and bottom film layers of the groove was measured, and the results are shown in Table 2 below.

[0049] Comparative Example 3 In this comparative example, the dimensions of the quartz boat are 600mm×400mm×400mm, and the dimensions of the groove are 3mm in length, 2mm in width, and 6mm in depth.

[0050] An electrostatic spraying method for applying an insulating film to the surface of a quartz boat includes the following steps: S0, a layer of primer with conductive particles is sprayed onto the surface of the quartz boat by air spraying, pre-cured at 50°C to form a primer film with conductive particles, the thickness of which is 20 micrometers; the primer with conductive particles can be silver, copper, nickel powder, or other primers with conductive particles (such as conductive carbon black).

[0051] S2, a polymer coating is formed by electrostatic spraying on a quartz boat with a conductive particle primer film using an electrostatic spraying gun. The electrostatic spraying parameters are shown in Table 1.

[0052] This step includes the following steps: S21, using an electrostatic spray gun to electrostatically spray polymer coatings onto a quartz boat.

[0053] S22, high-temperature melting to form a film.

[0054] S23, repeat S21~S22 until the coating thickness reaches the set target thickness.

[0055] The thickness of the top and bottom film layers of the groove was measured, and the results are shown in Table 2 below.

[0056] Table 1 Electrostatic spraying parameters Table 2 Film thickness As can be seen from Table 2, compared with Comparative Example 1, Example 1 reduced the ratio of the total thickness of the top and bottom film layers of the groove from 11.4 to 2.5 by pre-charging; compared with Comparative Example 2, Example 2 reduced the ratio of the total thickness of the top and bottom film layers of the groove from 7.1 to 1.6 by pre-charging; compared with Example 1, Example 2 reduced the ratio from 2.5 to 1.6, and the presence of a primer film without conductive particles preserved the surface charge for a longer period of time; although Comparative Example 3 also improved the ratio of the total thickness of the top and bottom film layers of the groove to some extent, the presence of conductive particles made the primer conductive process difficult to operate during primer formation, making it difficult to form a primer film of uniform thickness. Moreover, the method of Comparative Example 3 added non-insulating components to the insulating film, which degraded the performance of the quartz boat, contrary to the purpose of adding an insulating layer on the surface of the quartz boat.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for electrostatically spraying an insulating film onto the surface of a quartz boat, characterized in that, Includes the following steps: S1, the surface of the quartz boat is pre-charged through electrostatic induction; S2, using an electrostatic spray gun to electrostatically spray polymer coating onto a quartz boat to obtain a surface insulating film; Among them, in the surface insulating film, the ratio of the total thickness of the top surface film layer of the quartz boat to the total thickness of the bottom surface film layer of the groove is 1 to 3.

2. The electrostatic spraying method for the insulating film on the surface of a quartz boat according to claim 1, characterized in that, Before S1, there is also S0, which involves spraying a layer of primer without conductive particles onto the surface of the quartz boat by air spraying to form a primer film without conductive particles.

3. The electrostatic spraying method for the insulating film on the surface of a quartz boat according to claim 2, characterized in that, In S0, the sprayed primer is pre-cured to form a primer film without conductive particles, and the thickness of the primer film without conductive particles is 15 micrometers to 25 micrometers.

4. The electrostatic spraying method for the insulating film on the surface of a quartz boat according to claim 3, characterized in that, In S0, pre-curing is carried out at 35℃~60℃.

5. The electrostatic spraying method for the insulating film on the surface of a quartz boat according to claim 1, characterized in that, In S2, electrostatic spraying includes the following steps: S21, uses electrostatic spraying guns to electrostatically spray polymer coatings onto quartz boats; S22, melt-forming film; S23, repeat S21~S22 until the coating thickness reaches the set target thickness.

6. The electrostatic spraying method for the insulating film on the surface of a quartz boat according to claim 5, characterized in that, In S2, the parameters for electrostatic spraying are: electrostatic spraying voltage of 60 kV, electrostatic spraying current of 20 microamps, and single electrostatic spraying time of 20 seconds.

7. The electrostatic spraying method for the insulating film on the surface of a quartz boat according to claim 5, characterized in that, The polymer coating is one of epoxy resin coating, polyurethane coating, acrylic resin coating, and silicone coating, and the primer without conductive particles is one of epoxy resin insulating primer, polyurethane insulating primer, acrylic insulating primer, and silicone insulating primer.

8. The electrostatic spraying method for the insulating film on the surface of a quartz boat according to any one of claims 1-7, characterized in that, The dimensions of the quartz boat are 600mm×400mm×400mm, and the dimensions of the groove in the quartz boat are 3mm in length, 2mm in width, and 6mm in depth.

9. The electrostatic spraying method for applying an insulating film to the surface of a quartz boat according to any one of claims 1-7, characterized in that, In S1, the electrostatic generator is pre-charged with a voltage of 20 kV.

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