Preparation method of novel carbon-carbon low-temperature heater

Abstract

The invention discloses a preparation method of a novel carbon-carbon low heater. The preparation method comprises the following steps: needling; the preparation method comprises the following steps: cutting carbon fiber filaments into 50-100mm in length, and opening the cut carbon fiber filaments into a 50-200g / cm < 3 > net tire through a net opening machine to obtain a carbon-carbon low-heating net tire; hot pressing; the carbon-carbon low-heating net tire is soaked in the resin mixed liquid, a hot press is used for pressurization after soaking, after pressurization, the temperature is lowered to 90 DEG C or below, and a resin plate is taken out; the pressurized carbon-carbon low-heating net tire is obtained; performing carbonization; the hot-pressed carbon-carbon low-heating net tire is carbonized, the density reaches 1.7 g / cm < 3 > after carbonization, and the carbonized carbon-carbon low-heating net tire is obtained; performing impregnation; the carbonized carbon-carbon low-heating net tire is impregnated with phenolic resin, negative pressure is adopted during impregnation, the temperature is increased to 80-300 DEG C, and impregnation is conducted for 36 h; the impregnated carbon-carbon low-heating net tire is obtained; high temperature; and the impregnated carbon-carbon low-heating net tire is subjected to a high-temperature process, the density reaches 1.6 g / cm < 3 > after high temperature, and the carbon-carbon low-heating heater is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of heaters, in particular to a method for preparing a novel low-carbon heater. Background Art

[0002] Single crystal silicon material is the core basic material of modern electronic industry and photovoltaic industry, and its production quality directly affects the performance of downstream semiconductor devices and solar cells. The Czochralski method (CZ method for short) is one of the main processes for preparing single crystal silicon, and the performance of its core equipment, the single crystal furnace, plays a decisive role in the purity, crystal quality and growth efficiency of single crystal silicon.

[0003] In a single crystal furnace, the heater is a key component for melting silicon materials and controlling the temperature field. Traditional single crystal furnaces usually use graphite as the main material for the heater, especially in the manufacture of low heaters (lower heaters). Graphite materials are widely used due to their excellent thermal conductivity, high temperature resistance, thermal shock resistance and easy processing. However, with the continuous improvement of the semiconductor industry's requirements for the purity and crystal quality of single crystal silicon, the limitations of graphite materials have gradually emerged. Graphite is easily oxidized in high temperature environments, and its mechanical strength and deformation resistance are limited. Especially in long-term high-temperature use, problems such as structural degradation and impurity contamination will occur. These problems directly affect the production efficiency and quality of single crystal silicon.

[0004] In the prior art, the low-temperature heater of a single crystal furnace is usually made of graphite material. However, graphite material has the following problems in practical application:

[0005] High temperature oxidation problem: Graphite easily reacts with oxygen in high temperature environment and oxidizes, resulting in material loss and structural degradation. Although single crystal furnaces usually operate in a vacuum or inert gas environment, the oxidation problem is still difficult to completely avoid, especially after long-term operation, the service life of graphite is significantly limited;

[0006] Insufficient mechanical strength: The mechanical strength of graphite materials is limited. During the operation of the single crystal furnace, due to the combined effects of thermal stress and mechanical stress, the graphite low-temperature heater is prone to deformation or cracking, affecting the stability of the temperature field and the uniformity of crystal growth;

[0007] Short service life: Graphite low-temperature heaters will gradually degrade in high temperature environments, resulting in changes in resistance and reduced thermal efficiency, requiring frequent replacement, increasing production costs and maintenance difficulties. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a novel method for preparing a low-carbon heater.

[0009] The technical solution adopted by the present invention to solve the technical problem is:

[0010] A novel method for preparing a low carbon heater comprises the following steps:

[0011] Step 1: Needle punching: Cut the carbon fiber filaments into 50-100mm lengths and open them to 50-200g / cm by a mesh opening machine. 3 Net tire, obtain carbon-carbon low heating net tire;

[0012] Step 2, hot pressing; immerse the carbon-carbon low-heating mesh tire in the resin mixed liquid, and use a hot press to pressurize it after immersion. First, the temperature of the pressing plate is raised to 90°C; then the carbon-carbon low-heating mesh tire is placed on the pressing plate and a corresponding millimeter limit block is added to perform a hot pressing process, and then the temperature is lowered to below 90°C to take out the resin plate; the pressurized carbon-carbon low-heating mesh tire is obtained;

[0013] Step 3: Carbonization: The carbon-carbon low-heat mesh tire after hot pressing is carbonized, and inert gas is introduced during the carbonization process for protection; the density after carbonization reaches 1.7g / cm 3 , obtaining a carbonized carbon low heating web tire;

[0014] Step 4: Density after carbonization does not reach 1.7g / cm 3 , impregnate; use phenolic resin to impregnate the carbonized carbon-carbon low-heating mesh tire, under negative pressure during impregnation, heat to 80-300℃ and immerse for 36h; obtain the impregnated carbon-carbon low-heating mesh tire, and then continue the carbonization step, repeating this until the density after carbonization reaches 1.7g / cm 3 ;

[0015] Step 5, high temperature: the carbon-carbon low-heating mesh after impregnation is subjected to a high temperature process, and an inert gas protection is introduced at the same time. After high temperature, the density reaches 1.6g / cm 3 Circulation machine plus, get carbon low heater.

[0016] In one embodiment, the hot pressing process comprises:

[0017] 1MPA 90℃, 60min;

[0018] 2MPA 110℃, 15min;

[0019] 3MPA, 120℃, 10min;

[0020] 4MPA, 130℃, 10min;

[0021] 5MPA, 140℃, 30min;

[0022] 6MPA, 150℃, 30min;

[0023] 8MPA, 160℃, 30min;

[0024] 10-20MPA, 175℃, 120min.

[0025] In one embodiment, the carbonization step includes six carbonization steps:

[0026] (1). Reach 300℃ in 60min;

[0027] (2) 300 min to reach 450°C;

[0028] (3) 600 min to reach 550°C;

[0029] (4) 600min to 640℃;

[0030] (5) 600min to reach 780℃;

[0031] (6). Reach 840℃ in 750min.

[0032] In one embodiment, the temperature is automatically lowered after the six carbonization steps are completed.

[0033] In one embodiment, the high temperature step comprises six high temperature steps;

[0034] (1). Reach 300℃ in 60min;

[0035] (2) 300 min to reach 450°C;

[0036] (3). Reach 8000℃ in 600min;

[0037] (4) 600 min to reach 900°C;

[0038] (5). Reach 1800℃ in 600min;

[0039] (6). Reach 2200℃ in 50min.

[0040] In one embodiment, the temperature automatically decreases after the six high-temperature processes are completed.

[0041] In one embodiment, in the carbonization step, the pressurized carbon-carbon low-heating web is laid flat and passed through a 100 kg / m 2 Press with heavy objects; use sulfuric acid paper to separate to prevent carbonization and adhesion.

[0042] In one embodiment, in the high temperature, the impregnated carbon-carbon low-heating web is laid flat and passed through 100kg / m 2 Press with heavy objects and separate with sulfuric acid paper to prevent high temperature adhesion.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. Improve high temperature resistance: Carbon-carbon composite materials have excellent high temperature resistance, can maintain structural stability at extremely high temperatures (above 2000°C), and are not easily oxidized, thereby extending the service life of the heater.

[0045] 2. Enhanced mechanical strength and stability: The mechanical strength and thermal shock resistance of carbon-carbon composite materials are better than those of graphite. They can maintain stable shape and function in complex thermal stress environments, ensure the uniformity of the temperature field, and improve the growth quality of single crystal silicon.

[0046] 3. Reduce impurity content: Through precision processing and material purification technology, carbon-carbon composite materials can reduce the impurity content to an extremely low level, reduce the contamination of silicon melt, and improve the purity of single crystal silicon.

[0047] 4. Reduce maintenance and replacement frequency: Due to its longer service life and higher reliability, low-carbon heaters can significantly reduce replacement frequency, reduce production costs and the complexity of equipment maintenance.

[0048] By using carbon-carbon composite materials to replace traditional graphite materials, the overall performance of the single crystal furnace and the production efficiency of single crystal silicon can be improved to meet the increasingly stringent requirements of the semiconductor industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a process flow chart of Example 1 of the present invention. DETAILED DESCRIPTION

[0050] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0051] Example 1

[0052] like Figure 1 As shown, this embodiment includes the following steps:

[0053] Step 1: Needle punching: Cut the carbon fiber filaments into 50-100mm lengths and open them to 50-200g / cm by a mesh opening machine. 3 Net tire, obtain carbon-carbon low heating net tire;

[0054] Step 2, hot pressing; immerse the carbon-carbon low-heating mesh tire in a resin mixed liquid (phenolic resin PF9501B of Shengquan manufacturer: E51 resin AB of Yituo manufacturer: alcohol = 10:1:1), and pressurize it with a hot press after immersion. First, the temperature of the pressing plate is raised to 90°C; then the carbon-carbon low-heating mesh tire is placed on the pressing plate with a corresponding millimeter limit block, and a hot pressing process is performed. In this embodiment, the hot pressing process includes the following steps;

[0055] 1MPA 90℃, 60min;

[0056] 2MPA 110℃, 15min;

[0057] 3MPA, 120℃, 10min;

[0058] 4MPA, 130℃, 10min;

[0059] 5MPA, 140℃, 30min;

[0060] 6MPA, 150℃, 30min;

[0061] 8MPA, 160℃, 30min;

[0062] 10-20MPA, 175℃, 120min; then cool down to below 90℃ and take out the resin plate; obtain the pressurized carbon-carbon low-heating mesh tire;

[0063] Step 2: Carbonization: After hot pressing, the carbon-carbon low-heat mesh tire is carbonized, and inert gas is introduced during the carbonization process for protection; after carbonization, the density reaches 1.7g / cm 3 In this embodiment, the carbonization includes six carbonization steps;

[0064] (1). Reach 300℃ in 60min;

[0065] (2) 300 min to reach 450°C;

[0066] (3) 600 min to reach 550°C;

[0067] (4) 600min to 640℃;

[0068] (5) 600min to reach 780℃;

[0069] (6). Reach 840℃ in 750min; start to cool down automatically after the six carbonization steps are completed; obtain the carbonized carbon low-heating web tire;

[0070] Step 2: Density after carbonization does not reach 1.7g / cm 3 , impregnate; use phenolic resin to impregnate the carbonized carbon-carbon low-heating mesh tire, under negative pressure during impregnation, heat to 80-300℃ and immerse for 36h; obtain the impregnated carbon-carbon low-heating mesh tire, and then continue the carbonization step, repeating this until the density after carbonization reaches 1.7g / cm 3 ;

[0071] Step 5, high temperature: the carbon-carbon low-heating mesh after impregnation is subjected to a high temperature process, and an inert gas protection is introduced at the same time. After high temperature, the density reaches 1.6g / cm 3 Flow machine plus, in this embodiment, the high temperature step includes six high temperature processes;

[0072] (1). Reach 300℃ in 60min;

[0073] (2) 300 min to reach 450°C;

[0074] (3). Reach 8000℃ in 600min;

[0075] (4) 600 min to reach 900°C;

[0076] (5). Reach 1800℃ in 600min;

[0077] (6). Reach 2200℃ in 50min; start to cool down automatically after six high-temperature processes are completed; obtain a carbon-to-carbon low-temperature heater.

[0078] In one embodiment, in the carbonization step, the pressurized carbon-carbon low-heating web is laid flat and passed through a 100 kg / m 2 Press with heavy objects; use sulfuric acid paper to separate to prevent carbonization and adhesion.

[0079] In one embodiment, in the high temperature, the impregnated carbon-carbon low-heating web is laid flat and passed through 100kg / m 2 Press with heavy objects and separate with sulfuric acid paper to prevent high temperature adhesion.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the technical solutions of the present invention have been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A novel method for preparing a low carbon heater, characterized in that: The following steps are involved: Step 1: Acupuncture; Cut the carbon fiber filaments into 50-100mm lengths and open them to 50-200g / cm by a mesh opening machine. 3 Net tire, obtain carbon-carbon low heating net tire; Step 2, hot pressing; immerse the carbon-carbon low-heating mesh tire in the resin mixed liquid, and use a hot press to pressurize it after immersion. First, the temperature of the pressing plate is raised to 90°C; then the carbon-carbon low-heating mesh tire is placed on the pressing plate and a corresponding millimeter limit block is added to perform a hot pressing process, and then the temperature is lowered to below 90°C to take out the resin plate; the pressurized carbon-carbon low-heating mesh tire is obtained; Step 3: Carbonization: The carbon-carbon low-heat mesh tire after hot pressing is carbonized, and inert gas is introduced during the carbonization process for protection; the density after carbonization reaches 1.7g / cm 3 , obtaining a carbonized carbon low heating web tire; Step 4: Density after carbonization does not reach 1.7g / cm 3 , impregnate; use phenolic resin to impregnate the carbonized carbon-carbon low-heating mesh tire, under negative pressure during impregnation, heat to 80-300℃ and immerse for 36h; obtain the impregnated carbon-carbon low-heating mesh tire, and then continue the carbonization step, repeating this until the density after carbonization reaches 1.7g / cm 3 ; Step 5, high temperature: the carbon-carbon low-heating mesh after impregnation is subjected to a high temperature process, and an inert gas protection is introduced at the same time. After high temperature, the density reaches 1.6g / cm 3 Circulation machine plus, get carbon low heater.

2. The method for preparing a novel low carbon heater according to claim 1, characterized in that: The hot pressing process comprises: 1MPA 90℃, 60min; 2MPA 110℃, 15min; 3MPA, 120℃, 10min; 4MPA, 130℃, 10min; 5MPA, 140℃, 30min; 6MPA, 150℃, 30min; 8MPA, 160℃, 30min; 10-20MPA, 175℃, 120min.

3. The method for preparing a novel low carbon heater according to claim 1, characterized in that: In the carbonization step; there are six carbonization steps; (1). Reach 300℃ in 60min; (2) 300 min to reach 450°C; (3) 600 min to reach 550°C; (4) 600min to 640℃; (5) 600min to reach 780℃; (6). Reach 840℃ in 750min.

4. The method for preparing a novel low carbon heater according to claim 3, characterized in that: After the six carbonization steps are completed, the temperature will automatically drop.

5. The method for preparing a novel low carbon heater according to claim 1, characterized in that: In the high temperature step; there are six high temperature processes; (1). Reach 300℃ in 60min; (2) 300 min to reach 450°C; (3). Reach 8000℃ in 600min; (4) 600 min to reach 900°C; (5) 600 min to reach 1800°C; (6). Reach 2200℃ in 50min.

6. The method for preparing a novel low carbon heater according to claim 5, characterized in that: After the six high-temperature processes are completed, the temperature will automatically drop.

7. The method for preparing a novel low carbon heater according to claim 1, characterized in that: In the carbonization step, the pressurized carbon low-heated web is laid flat and passed through a 100 kg / m 2 Press with heavy objects; use sulfuric acid paper to separate to prevent carbonization and adhesion.

8. The method for preparing a novel low carbon heater according to claim 1, characterized in that: In the high temperature, the impregnated carbon low-heating mesh is laid flat and passed through 100kg / m 2 Press with heavy objects and separate with sulfuric acid paper to prevent sticking due to high temperature.

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