Preparation method of plasma-resistant ESCring for dry etching process

Abstract

The invention relates to the field of semiconductor manufacturing, and discloses a preparation method of a plasma-resistant ESCring for a dry etching process, and the ESCring is prepared from the following raw materials in parts by weight: 100 parts of 1000P FFKM raw glue and 0.5-1.5 parts of DBPH. The FFKM mixed rubber material is subjected to mold pressing according to three factors of vulcanization, the problem of material cleanliness is solved through raw material selection, a formula and a processing technology for preparing the ESCring rubber material, and ESCring has good physical and mechanical properties, excellent pressure change energy, super-strong medium resistance, excellent cleanliness and good plasma resistance, and can be used for preparing the ESCring rubber material. The sealing device is widely used for sealing a wafer dry etching process application system. The electrostatic chuck has the advantage of high durability so as to protect the electrostatic chuck from being damaged by high-energy plasma.

Description

Technical Field

[0001] The invention relates to the field of semiconductor manufacturing, and in particular to a method for preparing a plasma-resistant ESCring for a dry etching process. Background Art

[0002] Plasma-resistant ESC rings refer to electrostatic chuck (ESC) rings used in dry etching processes, which are specially designed to resist plasma erosion. Dry etching is a common process in semiconductor manufacturing that is used to create tiny structures on wafers through plasma etching. Plasma can etch materials in a high-energy state, and this high-energy environment can also cause damage to process equipment, especially the electrostatic chuck. The electrostatic chuck is used to fix and support the wafer during the etching process, and the ESC ring (ESC ring) is a part of the electrostatic chuck that is located around it to protect the chuck body from plasma erosion. Plasma-resistant ESC rings are made of special materials that can maintain stability and durability in high-temperature, high-energy plasma environments, thereby extending the life of the electrostatic chuck and ensuring the accuracy and consistency of the etching process. This type of ESC ring usually uses high-temperature and corrosion-resistant materials such as ceramics, quartz or special polymers to resist plasma erosion, while also reducing particle generation to avoid contamination of the wafer. Therefore, it is necessary to design a method for preparing a plasma-resistant ESCring for a dry etching process that has high durability to protect the electrostatic chuck from damage by high-energy plasma. Summary of the invention

[0003] 1. Technical issues to be solved

[0004] In view of the deficiencies in the prior art, the present invention provides a method for preparing a plasma-resistant ESCring for a dry etching process, which has the advantage of high durability to protect the electrostatic chuck from damage by high-energy plasma, and solves the problems in the above-mentioned background technology.

[0005] (II) Technical solution

[0006] In order to achieve the above-mentioned purpose of having high durability to protect the electrostatic chuck from damage by high-energy plasma, the present invention provides the following technical solution: a plasma-resistant ESCring for dry etching process, characterized in that it is made from the following raw materials in parts by weight: 100 parts of 1000P FFKM original rubber and 0.5-1.5 parts of DBPH.

[0007] Preferably, the molar content of F in the ESCring is 72% or more.

[0008] The high content of fluorine in the above scheme gives the material excellent chemical corrosion resistance and plasma erosion resistance, so that it can effectively resist the erosion and chemical attack of high-energy plasma in the dry etching process, thereby extending its service life. The high content of fluorine can also significantly reduce the surface energy of the material and reduce the adhesion of particles, thereby improving the accuracy and stability of the dry etching process. This makes the ESCring perform well in semiconductor manufacturing processes that require high durability and high purity, and is a key plasma-resistant consumable.

[0009] Preferably, the open mill processing conditions are as follows: the mixing temperature is 40°C-60°C, the rollers are kept cool by water, the speed ratio of the two rollers is 1.0:1.2-1.0:1.5, the number of thin passes is 5-10 times, and after each thin pass, the rubber material is refolded and passed through the rollers again to eliminate the existing uneven mixing or incompletely mixed components to prepare the FFKM mixed rubber material.

[0010] The above scheme is further adopted to ensure that the viscosity of the material is moderate within this temperature range, which can ensure that the components in the raw materials are fully mixed, while avoiding premature decomposition or volatilization of certain active substances at high temperatures, ensuring the uniformity and performance stability of the final product. During the processing, the roller temperature is controlled by cooling through water to ensure that the temperature is not too high during mixing, so as to prevent local overheating of the material from causing uneven mixing or performance degradation. At the same time, stable temperature control can extend the life of the processing equipment. The setting of the roller speed ratio can adjust the shear rate of the material, thereby controlling the mixing effect. The appropriate roller speed ratio can ensure that the material is appropriately sheared and extended during the mixing process, so that the components are better dispersed and mixed, and finally a uniform mixture is obtained. Thin pass means that during the open mixing process, the material is passed through the roller multiple times to make it more uniform and dense. The setting of the number of thin passes can further improve the mixing effect, ensure that the fillers and additives in the material are evenly distributed, reduce the generation of bubbles and other defects, and ultimately improve the density and plasma resistance of the ESC ring.

[0011] Preferably, the FFKM mixed rubber needs to be parked for 8-16 hours. During the parking process, it should be protected from light, temperature changes and moisture in the air, and the state of the rubber should be checked regularly.

[0012] The further resting process of the above scheme, also known as standing or aging, is to allow the mixed rubber to fully release the stress generated during the mixing process, so that the components in the rubber can be further evenly distributed and fused. During the resting period, the chemical reaction in FFKM can be gradually completed, so that the rubber can reach the best processing state. In addition, the control of the standing time between 8 and 16 hours can ensure that the rubber has good fluidity and stability in the subsequent processing and molding process, thereby improving the density and plasma resistance of the final product. This step is crucial to ensure the high quality and consistency of the ESC ring.

[0013] Preferably, the one-stage vulcanization processing condition is that after the ESCring is preheated in a vulcanizer, the cut mixed rubber material is accurately placed in a mold, and the temperature, time and pressure are controlled to pressurize and vulcanize for one stage. The one-stage vulcanization processing condition is (160±10℃)*(1000±10s)*(15±5MPa), that is, at a temperature of (160±10℃) for (1000±10 seconds) and a pressure of (15±5MPa) is applied.

[0014] The above scheme is adopted to further set the vulcanization temperature within this range, which can ensure that the vulcanizer in the FFKM material fully reacts to form a stable three-dimensional network structure. Too low a temperature may lead to incomplete vulcanization, while too high a temperature may cause material degradation. Therefore, the temperature is controlled at about 160°C to obtain the best vulcanization effect. The precise control of the vulcanization time is to ensure that the material reaches a sufficient degree of crosslinking. Too short a time may lead to insufficient crosslinking, while too long a time may cause over-vulcanization of the material, resulting in performance degradation. Therefore, a vulcanization time of about 1000 seconds is set to balance the crosslinking density and physical properties of the material. The pressure effect during the vulcanization process can ensure that the material is fully filled in the mold, eliminate bubbles and form a dense structure. The pressure control range is about 15MPa, which can ensure that the material forms a uniform density and structure during the vulcanization process and avoid molding defects caused by insufficient or excessive pressure.

[0015] Preferably, the ESCring formed in one stage is trimmed to remove excess material and burrs, and then placed in an oven for a second-stage vulcanization treatment. The processing conditions for the second-stage vulcanization are: gradually heating to 230°C at room temperature for 6 hours, and keeping the temperature constant for 10 hours after heating to 230°C. Finally, after completing the second-stage vulcanization treatment, slowly cool down to room temperature, take out the finished product and conduct a final inspection.

[0016] The further slow heating process using the above scheme allows the stress inside the material to be gradually released, avoiding thermal stress or thermal deformation caused by rapid heating. At the same time, the setting of the heating time ensures that the unfinished chemical reaction can continue at the low temperature stage, gradually increasing the cross-linking density. Long-term heat preservation at a high temperature of 230°C helps to fully complete the second-stage vulcanization reaction, so that the molecular structure of the material is further cross-linked and stabilized. This process can greatly improve the high temperature resistance and anti-aging properties of FFKM materials, and reduce performance degradation caused by high temperature environment in actual use.

[0017] Preferably, the two-stage vulcanization processing conditions are: use air medium for preliminary vulcanization treatment, place the ESCring on high temperature resistant PTFE paper, transfer to nitrogen medium for fine vulcanization treatment, and control the nitrogen pressure between 0.1-0.6MPa. By adjusting the pressure, after completing the two-stage vulcanization, gradually reduce the nitrogen pressure and cool down, and finally obtain an ESCring finished product with excellent performance.

[0018] The above scheme is used to further put the ESCring after the first stage of vulcanization into a vulcanization furnace, and the air in the furnace is used as the vulcanization medium for the second stage of vulcanization. This environment ensures uniform heating during the vulcanization process and avoids local unevenness that may occur when using other inert gases or vacuum environments. Vulcanization in an air medium can effectively promote further cross-linking of the material and enhance its surface stability while maintaining the physical properties of the material. This treatment method also helps to reduce the occurrence of internal defects and improve the overall quality of the material. During the second stage of vulcanization, the ESCring is carefully placed on PTFE paper for heating treatment. The main function of PTFE paper is to prevent adhesion between the contact surface of the ESC ring and the vulcanization furnace during the vulcanization process, and to avoid surface unevenness or material damage caused by direct contact. PTFE paper has excellent high temperature resistance and chemical inertness. It will not react chemically with the ESCring or affect the performance of the material during high temperature vulcanization. Its smooth surface can also ensure that the ESCring maintains good appearance quality during the vulcanization process and avoid indentations, scratches or other surface defects.

[0019] A method for preparing a plasma-resistant ESCring for a dry etching process comprises the following steps:

[0020] S1: In a clean mixer, add 100 parts of 1000P FFKM rubber;

[0021] S2: Continue stirring and kneading the mixture to fully mix the DBPH and 1000P FFKM rubber for 15-30 minutes;

[0022] S3: Take out the uniformly mixed raw materials, put them into a preforming mold, and perform preliminary forming at a pressure of 10-20 MPa for 5-10 minutes;

[0023] S4: placing the preformed material into a molding mold preheated to 230°C, and after the molding is completed, keeping the material in the mold gradually cooled to room temperature;

[0024] S5: After production, the ESC ring is subjected to various quality inspections, such as size inspection, hardness test, thermal shock resistance test, and plasma corrosion resistance test. The ESC ring that passes the inspection can enter the final assembly stage.

[0025] (III) Beneficial effects

[0026] Compared with the prior art, the present invention provides a method for preparing a plasma-resistant ESCring for a dry etching process, which has the following beneficial effects:

[0027] The present invention adopts FFKM raw rubber and small medicine to be matched, and processes according to the rubber mixing processing method to obtain FFKM mixed rubber for ESCring with excellent performance. The FFKM mixed rubber is molded according to the three elements of vulcanization, time, temperature and pressure, and the raw material selection, formula and processing technology of the ESCring rubber are prepared to solve the problem of material cleanliness. The ESCring has good physical and mechanical properties, excellent pressure change energy, super strong medium resistance, excellent cleanliness and good plasma resistance. It is widely used in wafer dry etching process application system sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the method of the present invention.

[0029] Figure 2 It is a schematic diagram of the thermogravimetric change of the present invention.

[0030] Figure 3 This is the energy spectrum of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the attached embodiment of the present invention Figure 1-Figure 3 , the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] A plasma-resistant ESCring for dry etching process, characterized in that it is made from the following raw materials in parts by weight:

[0034] 1000P FFKM original rubber 100 parts, DBPH 0.5-1.5 parts.

[0035] A method for preparing a plasma-resistant ESCring for a dry etching process comprises the following steps:

[0036] S1: In a clean mixer, add 100 parts of 1000P FFKM rubber;

[0037] In a clean mixer, add 100 parts of 1000P FFKM rubber and start the preliminary mixing of the materials. Make sure the operating environment of the mixer is dust-free and dry to prevent impurities from mixing in. Start the mixer and mix the FFKM rubber at a suitable temperature and roller speed to fully plasticize the FFKM rubber and prepare for the subsequent addition of other ingredients. During this process, the temperature control system of the equipment should be kept working normally to prevent the FFKM rubber from being degraded or changing in performance due to overheating.

[0038] S2: Continue stirring and kneading the mixture to fully mix the DBPH and 1000PFFKM rubber for 15-30 minutes;

[0039] Continue to stir and knead the mixture to fully mix the DBPH and 1000PFFKM rubber. During this process, keep the mixer running stably and ensure that all materials are evenly distributed in the equipment. The mixing time is set to 15 to 30 minutes to ensure that DBPH is fully dispersed into the FFKM rubber matrix, thereby ensuring the uniformity and performance consistency of the material. During the mixing process, it is necessary to regularly check the state of the mixture, adjust the stirring speed and temperature to prevent local overheating or unevenness of the material. After completion, the mixture should be properly cooled and treated for the next step of processing or use.

[0040] S3: Take out the uniformly mixed raw materials, put them into a preforming mold, and perform preliminary forming at a pressure of 10-20 MPa for 5-10 minutes;

[0041] Take the evenly mixed raw materials out of the mixer, make sure they are at the right temperature and free of impurities, then carefully place them into the pre-prepared pre-molding mold, make sure the raw materials are evenly distributed in the mold to avoid defects after molding, apply a pressure of 10 to 20 MPa to the raw materials in the mold for initial molding. This pressure range is sufficient to promote the initial molding of the material while ensuring the density of the internal structure of the material. The molding time is set to 5 to 10 minutes, which is enough time for the material to solidify under pressure and form the desired shape. After the initial molding is completed, take out the material from the mold, and properly cool and treat it to prepare for subsequent processing steps.

[0042] S4: placing the preformed material into a molding mold preheated to 230°C, and after the molding is completed, keeping the material in the mold gradually cooled to room temperature;

[0043] Carefully place the preformed material into the molding mold that has been preheated to 230°C, ensure that the material is evenly distributed in the mold to avoid unevenness or gaps during the molding process, start the molding equipment to further plasticize and mold the material at high temperature. After the molding process is completed, keep the material in the mold and gradually reduce the mold temperature to slowly cool it to room temperature. This gradual cooling process helps to avoid internal stress or warping of the material due to sudden temperature changes, and ensure that the molded material has good dimensional stability and mechanical properties. After cooling, take out the finished product from the mold and carry out necessary subsequent processing or testing to ensure that it meets the expected quality and performance standards.

[0044] S5: After production, the ESC ring is subjected to various quality inspections, such as size inspection, hardness test, thermal shock resistance test, and plasma corrosion resistance test. The ESC ring that passes the inspection can enter the final assembly stage.

[0045] After production, the ESC ring undergoes a series of rigorous quality inspections to ensure that it meets all design and performance standards. First, a dimensional inspection is performed. High-precision measuring tools such as vernier calipers or three-dimensional coordinate measuring machines are used to detect key dimensions such as the outer diameter, inner diameter, and thickness of the ESC ring to ensure that they are consistent with the design drawings. Next, a hardness test is performed, usually using a Shore hardness tester to measure the hardness of the material to verify whether it meets the specified mechanical performance requirements. Then, a thermal shock resistance test is performed to expose the ESC ring to alternating high and low temperature environments to evaluate its stability under extreme temperature changes and ensure that the material will not crack or deform due to temperature fluctuations during use. In addition, a plasma corrosion resistance test is required to detect whether there is wear or corrosion on the surface of the ESC ring by running it for a long time in a simulated plasma environment to ensure its durability in actual applications. ESC rings that pass all quality inspections will be marked as qualified products and then enter the final assembly link and be installed in the dry etching equipment to ensure the efficient operation of the entire production process and the stability of product quality.

[0046] Example 2

[0047] The present invention provides a technical solution: a method for preparing a plasma-resistant ESCring for a dry etching process, characterized in that it is prepared from the following parts by weight:

[0048] 1000PFFKM original rubber 100 parts, DBPH 0.5-1.5 parts.

[0049] Mixing materials: Weigh 1000PFFKM rubber and DBPH in proportion. Add the weighed 1000PFFKM rubber into the mixing container, and then gradually add DBPH. Use a mechanical stirrer to mix the two evenly, ensuring that the curing agent is evenly distributed in the FFKM rubber. The mixing process should be carried out at room temperature for 10-20 minutes until a uniform mixture is formed.

[0050] Molding: Place the mixed rubber in a preheated mold. The preheat temperature of the mold is set to 170°C. Spread the rubber evenly in the mold, making sure there are no bubbles or other defects. Then perform preliminary pressing in the mold and maintain pressure for 10-20 minutes.

[0051] Curing: Put the mold together with the rubber into a heating furnace for curing. The curing condition is 170℃ for 45 minutes. During the curing process, uniform temperature and pressure should be maintained to ensure the uniformity and stability of the material.

[0052] Demolding: After curing is completed, take the mold out of the heating furnace and demold it after cooling to room temperature. After demolding, the ESCring needs to be surface treated to remove excess burrs or residues on the surface. It can be lightly polished with sandpaper or cleaned with an appropriate solvent.

[0053] Final inspection: Check the dimensional accuracy, surface finish and physical properties of the ESCring. If all indicators meet the requirements, the ESCring is ready for use.

[0054] Example 3

[0055] Raw material weighing: According to the formula, weigh 100 parts by weight of 1000PFFKM original rubber and 0.5 parts by weight of DBPH to ensure the accuracy of raw material weighing.

[0056] Mixing process: add the weighed 1000PFFKM rubber into the open mixer for plasticizing. The plasticizing temperature is controlled between 60-70℃ for 3-5 minutes until the FFKM rubber softens and presents a uniform plastic state. While maintaining the plasticizing temperature, slowly add the weighed DBPH. Continue mixing for 6-8 minutes to ensure that the DBPH is evenly dispersed in the FFKM rubber.

[0057] Tablet forming: Transfer the mixed rubber to the tablet press, set the temperature to 60-70℃, and form the sheet. The thickness of the sheet is controlled at 2-3mm to ensure the uniformity and continuity of the sheet.

[0058] Vulcanization treatment: The molded ESCring sample was placed in a vulcanization furnace for secondary vulcanization. The vulcanization temperature was set at 180°C and the vulcanization time was 4 hours.

[0059] Performance test: After the sulfurization treatment, the ESCring samples were subjected to performance test. The test items included hardness, wear resistance and plasma tolerance. The test results showed that the ESCring prepared by this formula had moderate hardness, good wear resistance, and excellent tolerance under plasma conditions, and was suitable for use in dry etching processes.

[0060] The dosage of DBPH was adjusted to 1.0 part and 1.5 parts respectively. The results showed that with the increase of DBPH content, the plasma resistance and wear resistance of ESCring were improved, and the hardness of the material was slightly increased.

[0061] The experimental data are as follows:

[0062]

[0063]

[0064] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0065] Although 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 the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A plasma-resistant ESCring for dry etching process, characterized in that: Made from the following raw materials in parts by weight: 1000P FFKM original rubber 100 parts, DBPH 0.5-1.5 parts.

2. The method for preparing a plasma-resistant ESCring for dry etching process according to claim 1, characterized in that: The molar content of F in the ESCring is 72% or more.

3. The method for preparing a plasma-resistant ESCring for dry etching process according to claim 2, characterized in that: The open mill processing conditions are as follows: the mixing temperature is 40°C-60°C, the rollers are kept cool by water, the speed ratio of the two rollers is 1.0:1.2-1.0:1.5, the number of thin passes is 5-10 times, and after each thin pass, the rubber compound is refolded and passed through the rollers again to eliminate the existing uneven mixing or incompletely mixed components to make the FFKM mixed rubber compound.

4. The method for preparing a plasma-resistant ESCring for dry etching process according to claim 3, characterized in that: FFKM mixed rubber needs to be stored for 8-16 hours. During storage, it should be protected from light, temperature changes and moisture in the air, and the condition of the rubber should be checked regularly.

5. The method for preparing a plasma-resistant ESCring for dry etching process according to claim 4, characterized in that: After the ESCring is preheated in the vulcanizer, the cut mixed rubber material is accurately placed in the mold, and the temperature, time and pressure are controlled to pressurize and vulcanize for a period of time. The vulcanization processing conditions for this period are (160±10℃)*(1000±10s)*(15±5MPa), that is, at a temperature of (160±10℃) for (1000±10 seconds) and a pressure of (15±5MPa) is applied.

6. The method for preparing a plasma-resistant ESCring for dry etching process according to claim 5, characterized in that: The ESCring that has been formed in one stage is trimmed to remove excess material and burrs, and then placed in an oven for a second-stage vulcanization treatment. The processing conditions for the second-stage vulcanization are: gradually heating to 230°C at room temperature for 6 hours, and keeping the temperature constant for 10 hours after heating to 230°C. Finally, after completing the second-stage vulcanization treatment, slowly cool down to room temperature, take out the finished product and conduct final inspection.

7. The method for preparing a plasma-resistant ESCring for dry etching process according to claim 6, characterized in that: The two-stage vulcanization processing conditions are as follows: use air medium for preliminary vulcanization treatment, place the ESCring on high-temperature resistant PTFE paper, and transfer it to nitrogen medium for fine vulcanization treatment. The nitrogen pressure is controlled between 0.1-0.6MPa. By adjusting the pressure, after completing the two-stage vulcanization, the nitrogen pressure is gradually reduced and the temperature is lowered, and finally an ESCring finished product with excellent performance is obtained.

8. The method for preparing a plasma-resistant ESCring for dry etching process according to claim 7, characterized in that: The following steps are involved: S1: In a clean mixer, add 100 parts of 1000P FFKM rubber; S2: Continue stirring and kneading the mixture to fully mix the DBPH and 1000P FFKM rubber for 15-30 minutes; S3: Take out the uniformly mixed raw materials, put them into a preforming mold, and perform preliminary forming at a pressure of 10-20 MPa for 5-10 minutes; S4: placing the preformed material into a molding mold preheated to 230°C, and after the molding is completed, keeping the material in the mold gradually cooled to room temperature; S5: After production, the ESC ring is subjected to various quality inspections, such as size inspection, hardness test, thermal shock resistance test, and plasma corrosion resistance test. The ESC ring that passes the inspection can enter the final assembly stage.

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