Opaque quartz glass with high absorption

Abstract

The invention relates to opaque quartz glass with high absorption in the near-infrared range and a production method thereof. The invention also relates to the use of the opaque quartz glass according to the invention or of the opaque quartz glass obtained from the method according to the invention in a processing chamber in which semiconductor wafers are processed.

Description

Opaque quartz glass with high absorption

[0001] This invention relates to an opaque quartz glass with high absorption in the visible and infrared wavelength range of 0.2µm to 10µm, and a method for producing the same. The invention also relates to the use of the opaque quartz glass according to the invention, or the opaque quartz glass obtained from the method according to the invention, in a processing chamber in which semiconductor wafers are processed.

[0002] Various devices, such as reactors, equipment, support plates, bell jars, crucibles, protective shields, or simpler components (such as tubes, rods, plates, flanges, rings, or blocks), are used in the production of semiconductor components and optical displays. These devices must meet high requirements in terms of purity, chemical and thermal stability, and mechanical strength. They can be made of, for example, stainless steel, but increasingly, quartz glass. This is because high-purity silica is inert to conventional semiconductor materials. Quartz glass is also characterized by its high chemical stability relative to many process media and its high resistance to thermal shock.

[0003] In processing chambers where semiconductor wafers are processed at high temperatures, some components are heated by radiation from lamps. To ensure rapid and efficient heat transfer, the materials used for this purpose must have high absorption from the visible wavelength range to the near-infrared, i.e., in the range of 0.4 μm to 3 μm. Since the components must also have low thermal mass to enable rapid thermal cycling of heating and cooling, high absorption must be achieved even when the components are very thin or have small wall thicknesses. Because process control is difficult when the absorption of a material is highly temperature-dependent, it is advantageous for absorption to depend on temperature to the minimum possible extent. These (infrared) optical properties should be combined, as far as possible, with the proven properties of high-purity quartz glass for application in processing chambers used for wafer fabrication.

[0004] In addition, components made of other materials, high-purity silicon carbide (e.g., CVD-SiC), and high-purity Si are also used. However, the production and processing of these materials are significantly more complex and expensive than that of quartz glass.

[0005] Corresponding quartz glass materials are described, for example, in EP 3 068 739 A. The described material is a composite material comprising a matrix made of quartz glass, with silicon-containing regions embedded within the matrix. Although the composite material exhibits high absorption in the near-infrared at visible wavelengths up to 1 μm, the absorption decreases significantly at room temperature. Only at higher temperatures does the absorption increase for wavelengths greater than 1 μm, reaching a constant value from approximately 1000 °C. However, at lower temperatures, the infrared absorption is highly temperature-dependent, making process control difficult and therefore disadvantageous.

[0006] Another composite material for use in processing chambers for wafer fabrication is known from US 2001 / 025001 A. This composite material consists of quartz glass and a second phase made of silicon, silicon carbide, silicon nitride, titanium nitride, or titanium carbide. The object of this invention is to provide a material that is less prone to cracking and releases fewer particles during machining than quartz glass. Due to this production method, the composite material has an open porosity of less than 15% or less than 5%. Open-pore materials are very difficult to clean, especially with liquids or acids. During machining, impurities can penetrate into the open pore channels. It is practically impossible to remove these impurities without leaving residue. Furthermore, the optical properties of the resulting material are not described, and the material obtained from US 2001 / 025001 A contains carbon as long as silicon carbide is the second phase in the composite material. This is caused by the production method used: silicon carbide as the starting material always contains carbon as an impurity, and this is not removed in the described production method of vacuum sintering under pressure.

[0007] JP 2006 / 027930 A relates to a black quartz glass, wherein the black color is due to the incorporation of graphite particles. The quartz glass is produced by sintering from a mixture of amorphous quartz glass powder (fly ash) and graphite powder having a defined particle size distribution. The carbon particles used account for 0.05% to 2% by weight of SiO2 and have a diameter of 0.07 μm to 0.5 μm or 0.05 μm to 1 μm. In particular, ground quartz glass is used as the SiO2 powder, which is produced by flame hydrolysis in a hydrogen / oxygen flame. The resulting material is sintered at 1100°C to 1500°C. At excessively high temperatures, a decrease in the density of the quartz glass is observed due to the formation of bubbles. The resulting quartz glass contains elemental carbon, which is disadvantageous for certain applications.

[0008] JPH05170477 A relates to a black quartz glass and a cell for optical analysis using the glass. The quartz glass is doped with 0.05 wt% to 0.3 wt% SiC (based on a C concentration meter). Devitrification stability is improved by doping with nitrogen (10 ppm to 5000 ppm), fluorine (10 ppm to 5000 ppm), and chlorine (10 ppm to 1000 ppm). The transmittance is at most 1% with a layer thickness of 1 mm in the wavelength range of 200 nm to 25,000 nm. The resulting quartz glass contains elemental carbon, which is disadvantageous for some applications.

[0009] US 5,674,792 relates to a method for preparing an opaque quartz glass material from a slurry (slurry casting method); the described material contains only SiO2 particles and pores.

[0010] A known drawback of these composite materials from the prior art is that the absorption of SiO2 / Si composites at wavelengths greater than 1 µm is low at room temperature due to the Si content and is also highly temperature-dependent. A disadvantage of SiO2 / SiC composites made from high-purity raw materials is their low absorption at wavelengths less than 1 µm. Impurities, especially metal compounds, can enhance absorption in this range, but are undesirable in materials used for semiconductor applications. The proportion of elemental carbon is also disadvantageous.

[0011] Therefore, the object of the present invention is to provide a composite material that exhibits the highest possible absorption from the visible to near-infrared range (i.e., 0.4 μm to 3 μm) even at room temperature, and that the composite material also exhibits low temperature dependence on absorption. These (infrared) optical properties should be combined with the proven properties of high-purity quartz glass for application in processing chambers used for wafer fabrication. These desired properties are particularly selected from high purity, high temperature resistance, high thermal shock resistance, high chemical resistance, good electrical insulation, good mechanical strength, the possibility of residue-free cleaning (e.g., by ultrasonic cleaning and hydrofluoric acid (HF) cleaning), mechanical machinability, low particle release during the process, and low production costs compared to high-purity ceramics.

[0012] These objectives are achieved in the context of this invention by a composite material having a matrix made of quartz glass, wherein regions containing silicon phase and regions containing silicon carbide phase are embedded in the matrix.

[0013] The present invention relates to a composite material having a matrix made of quartz glass, wherein regions containing a silicon phase and regions containing a silicon carbide phase are embedded in the matrix.

[0014] According to the present invention, a composite material having a matrix made of quartz glass and having embedded regions of silicon-containing phase and silicon carbide-containing phase has been found to have high absorption from the visible to near-infrared (i.e., 0.4 μm to 3 μm) even at room temperature, and also has low temperature dependence absorption, and is therefore ideally suited for processing chambers for wafer processing.

[0015] Compared to the composite material made of SiO2 and silicon described in EP 3 068 739 A, the composite material according to the present invention has significantly higher absorption at wavelengths greater than 1 μm in the infrared range at temperatures below or equal to 1000 °C. Furthermore, the temperature dependence of the material's absorption in this wavelength range is far less than that of the equivalent composite material according to EP 3 068 739 A.

[0016] In the context of this invention, silicon-containing phase means a phase containing elemental / metallic silicon.

[0017] In the context of this invention, a silicon carbide-containing phase means a phase containing silicon carbide.

[0018] The matrix of the composite material according to the invention is opaque, translucent, or transparent. Within the matrix, there are regions containing silicon (Si) in elemental form, referred to herein as the silicon-containing phase, in a very fine distribution. Also within the matrix, there are regions containing silicon carbide (SiC), referred herein as the silicon carbide-containing phase, in a very fine distribution.

[0019] These regions affect the overall heat absorption of the composite material according to the invention. This is primarily due to the properties of the semiconductor elements silicon and silicon carbide.

[0020] The composite material according to the invention has high absorption from the visible to near-infrared (i.e., 0.4 μm to 3 μm), and therefore, the material can be heated efficiently and rapidly even with small wall thicknesses.

[0021] The silicon-containing and silicon carbide-containing phases are very finely and uniformly distributed within the quartz glass matrix. Although they can be directly located on the surface of the composite material, a coating to prevent oxidation is not necessary. Otherwise, the coating would result in additional undesirable reflections at the interface with the composite material.

[0022] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably less than or equal to 10% by weight, more preferably less than or equal to 9% by weight, even more preferably less than or equal to 8% by weight, even more preferably less than or equal to 7% by weight, even more preferably less than or equal to 6% by weight, even more preferably less than or equal to 5% by weight, based on the matrix made of quartz glass in each case.

[0023] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably greater than or equal to 0.25% by weight, more preferably greater than or equal to 0.5% by weight, even more preferably greater than or equal to 1% by weight, even more preferably greater than or equal to 1.5% by weight, even more preferably greater than or equal to 2% by weight, even more preferably greater than or equal to 2.5% by weight, based on the matrix made of quartz glass in each case.

[0024] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on the matrix made of quartz glass in each case.

[0025] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably less than or equal to 20% by weight, more preferably less than or equal to 15% by weight, more preferably less than or equal to 10% by weight, more preferably less than or equal to 9% by weight, even more preferably less than or equal to 8% by weight, even more preferably less than or equal to 7% by weight, even more preferably less than or equal to 6% by weight, even more preferably less than or equal to 5% by weight.

[0026] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably greater than or equal to 0.25 wt%, more preferably greater than or equal to 0.5 wt%, even more preferably greater than or equal to 1 wt%, even more preferably greater than or equal to 1.5 wt%, even more preferably greater than or equal to 2 wt%, even more preferably greater than or equal to 2.5 wt%, based on the matrix made of quartz glass in each case.

[0027] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably 0.25% to 20% by weight, more preferably 0.25% to 15% by weight, more preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on the matrix made of quartz glass in each case.

[0028] As the proportion of silicon carbide increases, the porosity increases, leading to a decrease in mechanical strength and a deterioration in the surface finish of machined parts. Composites with a silicon carbide content higher than 20% by weight can generally no longer be densely sintered under atmospheric conditions; that is, the material has open porosity. Specifically, impurities contained in the liquid can then penetrate deeply into the composite material, for example, during machining, and are practically impossible to remove. It is then generally no longer possible to clean the surface with hydrofluoric acid (HF) because the acid penetrates the material and dissolves it.

[0029] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably less than or equal to 10% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0030] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably less than or equal to 9% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0031] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably less than or equal to 8% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0032] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably less than or equal to 7% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0033] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably less than or equal to 6% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0034] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably less than or equal to 5% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0035] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably greater than or equal to 0.25% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably from 0.25% to 10% by weight, more preferably from 0.5% to 9% by weight, even more preferably from 1% to 8% by weight, even more preferably from 1.5% to 7% by weight, even more preferably from 2% to 6% by weight, even more preferably from 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0036] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably greater than or equal to 0.50% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably from 0.25% to 10% by weight, more preferably from 0.5% to 9% by weight, even more preferably from 1% to 8% by weight, even more preferably from 1.5% to 7% by weight, even more preferably from 2% to 6% by weight, even more preferably from 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0037] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably greater than or equal to 1 wt% based on the matrix made of quartz glass in each case, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably 0.25 wt% to 10 wt%, more preferably 0.5 wt% to 9 wt%, even more preferably 1 wt% to 8 wt%, even more preferably 1.5 wt% to 7 wt%, even more preferably 2 wt% to 6 wt%, even more preferably 2.5 wt% to 5 wt% based on the matrix made of quartz glass in each case.

[0038] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably greater than or equal to 1.5% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0039] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably greater than or equal to 2% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0040] The weight percentage of the silicon-containing phase in the composite material according to the invention is preferably greater than or equal to 2.5% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon carbide-containing phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0041] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably less than or equal to 10% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0042] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably less than or equal to 9% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0043] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably less than or equal to 8% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0044] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably less than or equal to 7% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0045] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably less than or equal to 6% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0046] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably less than or equal to 5% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0047] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably greater than or equal to 0.25% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably from 0.25% to 10% by weight, more preferably from 0.5% to 9% by weight, even more preferably from 1% to 8% by weight, even more preferably from 1.5% to 7% by weight, even more preferably from 2% to 6% by weight, even more preferably from 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0048] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably greater than or equal to 0.50% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably from 0.25% to 10% by weight, more preferably from 0.5% to 9% by weight, even more preferably from 1% to 8% by weight, even more preferably from 1.5% to 7% by weight, even more preferably from 2% to 6% by weight, even more preferably from 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0049] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably greater than or equal to 1 wt% in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably 0.25 wt% to 10 wt%, more preferably 0.5 wt% to 9 wt%, even more preferably 1 wt% to 8 wt%, even more preferably 1.5 wt% to 7 wt%, even more preferably 2 wt% to 6 wt%, even more preferably 2.5 wt% to 5 wt%, based on a matrix made of quartz glass.

[0050] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably greater than or equal to 1.5% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0051] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably greater than or equal to 2% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably 0.25% to 10% by weight, more preferably 0.5% to 9% by weight, even more preferably 1% to 8% by weight, even more preferably 1.5% to 7% by weight, even more preferably 2% to 6% by weight, even more preferably 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0052] The weight percentage of the silicon carbide phase in the composite material according to the invention is preferably greater than or equal to 2.5% by weight in each case, based on a matrix made of quartz glass, while the weight percentage of the silicon phase in the composite material according to the invention is preferably from 0.25% to 10% by weight, more preferably from 0.5% to 9% by weight, even more preferably from 1% to 8% by weight, even more preferably from 1.5% to 7% by weight, even more preferably from 2% to 6% by weight, even more preferably from 2.5% to 5% by weight, based on a matrix made of quartz glass.

[0053] The thermal absorption of the composite material according to the invention depends on the proportions of the silicon-containing phase and the silicon carbide-containing phase. The higher the proportions of these phases, the higher the absorptivity and emissivity. Therefore, the weight ratio of the silicon-containing phase and the silicon carbide-containing phase should preferably be higher than the minimum amount defined above. On the other hand, a high volume ratio of silicon-containing and silicon carbide-containing phases may complicate the production of the composite material, and therefore the maximum amount given above represents a suitable upper limit. The silicon-containing phase is mainly responsible for absorption at wavelengths less than 1 μm, while the silicon carbide-containing phase is mainly responsible for absorption in the infrared wavelength range greater than 1 μm to 5 μm.

[0054] The matrix of the composite material according to the invention preferably consists of quartz glass having a hydroxyl content of up to 30 ppm by weight. Hydroxyl groups lead to a decrease in the viscosity of the quartz glass. Therefore, hydroxyl groups are detrimental to high dimensional stability under thermal stress, and thus the maximum amount mentioned above should preferably be observed.

[0055] The hydroxyl content of transparent quartz glass is typically determined using infrared transmission measurements. However, this method is not readily applicable to endothermic composites. Therefore, the hydroxyl content of the composite material is determined by emission measurements in the absorption wavelength region (at 2.72 μm) of hydroxyl groups in quartz glass, by comparison with a standard having a known hydroxyl content.

[0056] The matrix of the composite material according to the invention may consist of undoped or doped quartz glass. In the context of the invention, in addition to SiO2, the doped quartz glass may also contain other oxide, nitride, or carbide components in amounts of up to 1000 ppm.

[0057] The silicon-containing phase region is preferably formed of particulate silicon. In this case, the d90 value of the silicon particle size distribution is preferably less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm.

[0058] The region containing the silicon carbide phase is preferably formed of particulate silicon carbide. In this case, the d90 value of the particle size distribution of the silicon carbide particles is preferably less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm.

[0059] In the context of this invention, the average size of the silicon particles and silicon carbide particles is particularly preferably suited to the average particle size of the SiO2 matrix particles, so that no undesirable separation effect due to sedimentation occurs during the production of the composite material according to the invention.

[0060] The particle size distribution d90 of silicon particles in the composite material according to the present invention is preferably less than 100 μm, while the particle size distribution d90 of silicon carbide particles is preferably less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm.

[0061] The particle size distribution d90 of silicon particles in the composite material according to the present invention is preferably less than 75 μm, while the particle size distribution d90 of silicon carbide particles is preferably less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm.

[0062] The particle size distribution d90 of silicon particles in the composite material according to the present invention is preferably less than 50 μm, and the particle size distribution d90 of silicon particles is preferably less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm.

[0063] The particle size distribution d90 of silicon carbide particles in the composite material according to the present invention is preferably less than 100 μm, while the particle size distribution d90 of silicon particles is preferably less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm.

[0064] The particle size distribution d90 of silicon carbide particles in the composite material according to the present invention is preferably less than 75 μm, while the particle size distribution d90 of silicon particles is preferably less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm.

[0065] The particle size distribution d90 of silicon carbide particles in the composite material according to the present invention is preferably less than 50 μm, while the particle size distribution d90 of silicon particles is preferably less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm.

[0066] Particle size distribution was measured by laser diffraction using a Mastersizer 3000 from Malvern.

[0067] In the composite material according to the invention, silicon carbide in the silicon carbide-containing phase can exist in any variant. In the context of the invention, it is preferred that the silicon carbide in the composite material according to the invention exists in α-SiC and / or β-SiC variants. Particularly preferred is that the silicon carbide in the composite material according to the invention exists in the α-SiC variant.

[0068] For the intended use of the composite material according to the invention, it is preferred that the composite material has high purity. Therefore, the maximum permissible impurities in the corresponding components of the composite material according to the invention are preferably subject to certain limitations, which will be described in more detail below.

[0069] Firstly, preferably, the silicon-containing phase contains preferably less than 50 ppm, more preferably less than 25 ppm, and even more preferably less than 10 ppm of metallic impurities, which are determined by glow discharge spectroscopy.

[0070] Therefore, it is also preferred that the silicon carbide phase contains preferably less than 50 ppm, more preferably less than 25 ppm, and even more preferably less than 10 ppm of metallic impurities, which are determined by glow discharge spectroscopy.

[0071] Further preferably, the matrix made of quartz glass contains preferably less than 100 ppm, more preferably less than 50 ppm, and even more preferably less than 25 ppm of metallic impurities, which are determined by inductively coupled plasma optical emission spectroscopy.

[0072] Further preferably, the composite material according to the invention contains preferably less than 100 ppm, more preferably less than 50 ppm, and even more preferably less than 25 ppm of metallic impurities, which are determined by inductively coupled plasma optical emission spectroscopy.

[0073] Metallic impurities include alkali metals, alkaline earth metals, transition metals, and other metals classified in the periodic table.

[0074] A low cristobalite content of 1% or less in the matrix ensures a low tendency for devitrification and thus a low risk of cracking during operation.

[0075] In the context of this invention, iron and copper should be avoided as metallic impurities.

[0076] Furthermore, and particularly preferably, the composite material according to the invention has a carbon content of less than 0.1% by weight, more preferably less than 0.075% by weight, and even more preferably less than 0.05% by weight, based on the total weight of the composite material in each case. Specifically, the composite material according to the invention is carbon-free.

[0077] The low carbon content in the composite material according to the invention is achieved by the production method described below. During the production process of the composite material according to the invention, the composite material is sintered at high temperature in an air atmosphere, i.e., in the presence of oxygen, thereby resulting in a low carbon content.

[0078] For the intended use of the composite material according to the invention, it is preferred that the composite material has a low porosity.

[0079] Therefore, it is preferred that the composite material according to the invention has a porosity of less than 2%, more preferably less than 1.5%, and even more preferably less than 1%, which is defined as the pore volume based on the total volume of the composite material.

[0080] Specifically, preferably, the composite material according to the present invention does not have open-pore porosity.

[0081] The large pores in the composite material according to the invention can contribute to undesirable diffuse reflection. The low porosity of the composite material of the invention limits this effect. Furthermore, the matrix preferably contains small pores with a maximum pore size of less than 10 μm. The pores are primarily formed between sintered SiO2 particles and generally have a non-circular shape.

[0082] The low porosity and small pore size achieved by the composite material according to the invention also bring further technical advantages, such as high strength, high etch resistance (e.g., during wet etching with HF (an acid commonly used to clean quartz glass components)) and low roughness of mechanically polished surfaces.

[0083] Due to the low porosity and associated low diffuse reflection of the quartz glass matrix, visible and infrared radiation can penetrate deeply into the matrix and thus reach deeper absorption centers composed of silicon-containing and silicon carbide-containing phases. This contributes to greater absorption.

[0084] Microscopic images and dye penetration tests show that the composite material according to the present invention has no open-cell porosity. The residual pores remaining after sintering are closed-cell.

[0085] Due to this preferred porosity according to the invention, the resulting composite material can be cleaned without leaving any residue. For this purpose, ultrasonic cleaning or cleaning with hydrofluoric acid (HF) is suitable, for example.

[0086] The composite material according to the invention has a reflectance value of preferably 2 to 30, more preferably 3 to 25, and even more preferably 4 to 20. In the context of the invention, the reflectance value (Y value in the Yxy color space) is measured using a Chroma Meter CR-410 colorimeter from Konica Minolta.

[0087] The composite material according to the invention, when used to make a 3 mm thick disk, exhibits hemispherical transmittance of less than 1%, more preferably less than 0.8%, and even more preferably less than 0.6% in the visible and near-infrared range of 400 nm to 2500 nm, thus making the composite material according to the invention particularly advantageous for the intended use described below. Transmittance is measured using a spectrometer (grating spectrometer), with an integrating sphere used to integrate the reflected and transmitted radiation, thereby enabling the measurement of hemispherical reflection and transmission.

[0088] The 3mm thick disk made of the composite material according to the invention has, in various cases, a hemispherical reflection of preferably less than 70%, more preferably less than 60%, and even more preferably less than 50% at a wavelength of 1500nm.

[0089] The 3mm thick disk made of the composite material according to the invention has, in various cases, a hemispherical reflectance of preferably less than 50%, preferably less than 40%, and even more preferably less than 30% in the visible wavelength range of 400nm to 800nm.

[0090] Furthermore, the 3mm disk of the composite material according to the present invention exhibits a small change in absorptivity (or emissivity) at a wavelength of 1.5μm in NIR between room temperature (20°C) and 1000°C. The change in absorptivity (or emissivity) is preferably less than 0.3, more preferably less than 0.2, and particularly preferably less than 0.1.

[0091] The emissivity mentioned here refers to "normal spectral emissivity." This value is determined based on a measurement principle known as the "blackbody boundary condition" (BBC) and was presented in "DETERMINING THE TRANSMITTANCE AND EMITTANCE OF TRANSPARENT AND SEMITRANSPARENT MATERIALS AT ELEVATED TEMPERATURES"; J. Manara, M. Keller, D. Kraus, M. Arduini-Schuster; 5th European Thermal-Sciences Conference, Netherlands (2008). According to Kirchhoff's radiation law, the normal spectral emissivity of any object is equal to its normal spectral absorptivity (abbreviated here as absorption).

[0092] For room temperature, the absorption A is calculated from the measured hemispherical reflectance R and the measured hemispherical transmission T using the following equation:

[0093] A = 1 – R – T.

[0094] The composite material according to the invention preferably has a content of at least 2.19 g / cm³. 3 More preferably at least 2.20 g / cm³ 3 Or even more preferably at least 2.21 g / cm³ 3 The specific gravity, which is determined according to the Archimedes method.

[0095] Since the composite material according to the invention does not have open-pore porosity, a simple density measurement based on Archimedes' principle is possible. Porosity is determined using density measurement, which takes into account the specific composition of the composite material according to the invention and the specific gravities of the quartz glass matrix, the silicon-containing phase, and the silicon carbide-containing phase, and thus calculates the porosity (the ratio of pore volume to total volume) as defined above from the specific gravities and proportions of the components used in the composite material according to the invention.

[0096] The composite material according to the invention differs from the composite material described in EP 3 068 739 A in that it additionally incorporates silicon carbide particles. The composite material according to the invention does not have open-cell porosity and is therefore different from the still open-cell silicon composite material described in US2001 / 025001 A. To achieve the desired absorption, it is also not necessary to have the same high proportion of silicon and silicon carbide as the material described in US2001 / 025001 A.

[0097] The difference in material properties between the material described in US 2001 / 025001 A and the composite material according to the present invention is due to different production methods. The composite material according to the present invention is produced by slip casting as described below, thereby obtaining a preform with a higher density than the preform produced by dry pressing as described in US 2001 / 025001 A. Therefore, a high-density composite material without open-pore porosity can be achieved by atmospheric sintering even at temperatures below 1400°C, while the dry-pressed Si composite material from US 2001 / 025001 A remains open-pore even when hot-pressed at 1400°C under high pressure (20 MPa to 40 MPa). It is impossible to fully sinter the dry-pressed preform under atmospheric conditions.

[0098] Compared to the SiO2 / Si composite material described in EP 3 068 739 A, the composite material according to the present invention exhibits significantly higher absorption at wavelengths greater than 1 μm in the infrared range at temperatures below 1000 °C. Furthermore, the absorption of the material in this wavelength range is much less dependent on temperature.

[0099] As described below, the composite material according to the invention is sintered under normal atmospheric conditions. Under these sintering conditions, any plastic particles and organic compounds still contained in the powder and the resulting green body (e.g., abrasion from containers and tools, additives such as binders or filter aids), as well as elemental carbon residues due to common impurities in silicon carbide, are burned off and thus removed by reacting with oxygen contained in the air. These reactions occur during heating of the green body at temperatures below 1000°C, where the molded body remains open and the resulting gaseous compounds can easily escape.

[0100] The silicon carbide-containing composite materials described in US 2001 / 025001 A must be sintered under vacuum and pressure to achieve closed-cell porosity. Therefore, these composite materials still contain residual elemental carbon.

[0101] The present invention also relates to a method for producing composite materials, and particularly for producing composite materials as described above.

[0102] The method according to the present invention is characterized by the following method steps:

[0103] a. Provide a mixture comprising amorphous quartz glass particles, silicon-containing powder, and silicon carbide-containing powder as a suspension;

[0104] b. To obtain a preform by forming a molded body from the suspension generated in step a. of method by slip casting;

[0105] c. Drying the blank; and

[0106] d. Sintering the dried green body obtained from step c.

[0107] The specific details of the individual components described above, such as particle size, particle size distribution, purity, etc., can also be applied to the method according to the present invention, with necessary modifications.

[0108] Method step a. is preferably performed by mixing silicon-containing powder and silicon carbide-containing powder into an aqueous suspension composed of quartz glass particles. Additionally, in method step a., additives known from ceramic processing technology, such as dispersants, filter aids, and binders, may be added.

[0109] The particle size distribution of the quartz glass particles in the suspension provided in step a. has a d90 value, preferably less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm, as determined by laser diffraction according to ISO 2019:13320 in each case.

[0110] The solid content in the aqueous suspension of quartz glass particles provided in step a. is preferably more than 50% by weight, more preferably more than 65% by weight, and even more preferably more than 75% by weight. The same solid content is also achieved for the resulting mixture of quartz glass particles, silicon-containing powder, and silicon carbide-containing powder.

[0111] Silicon-containing powders and silicon carbide-containing powders can be mixed with quartz glass powders before the suspension is formed. For example, dry mixing is suitable for this purpose.

[0112] However, it has been shown that it is particularly advantageous to mix silicon-containing powder and silicon carbide-containing powder into a liquid containing amorphous quartz glass powder, as already mentioned.

[0113] In step a of the production method according to the invention, silicon-containing powder and silicon carbide-containing powder may preferably be mixed in a mixing system having an agitator or a dissolver into a liquid containing quartz glass particles.

[0114] Before removing the liquid, the silicon-containing powder and the silicon carbide-containing powder are mixed. Uniform mixing is particularly easy to achieve in the suspension.

[0115] The solids content, particle size, and particle size distribution of quartz glass particles affect the shrinkage of the preform during subsequent drying. For example, shrinkage during drying can be reduced by using relatively coarse SiO2 particles. In this context, the defined quartz glass powder refers to those quartz glass powders in which amorphous quartz glass particles have a particle size in the range of up to 200 μm, more preferably up to 100 μm, wherein quartz glass particles having a particle size between 1 μm and 60 μm constitute the maximum volume proportion of the quartz glass powder.

[0116] In step b of the production method according to the invention, a slurry molding method is performed, in which a mixed suspension of quartz glass particles, silicon powder and silicon carbide powder is filled into a mold containing porous components through which some water is removed from the suspension, thereby forming a dimensionally stable body.

[0117] In step c. of the method, the blank is preferably removed from the mold and dried, wherein any residual water remaining in the blank is evaporated.

[0118] The dried green body obtained from method step c. preferably has a content greater than or equal to 1.60 g / cm³. 3 More preferably greater than or equal to 1.65 g / cm³ 3 Even more preferably, greater than or equal to 1.70 g / cm³ 3 The density.

[0119] The slip casting method according to the present invention produces an intermediate state in the form of a preform. Both the slip casting method for the preform and the intermediate product allow for measures to be taken to adjust and modify the properties affecting the final composite material.

[0120] Therefore, processing the starting powders in a suspension facilitates their close mixing and uniform distribution within the green body. The liquid also acts as a binder or activator between the solid components. The liquid can modify the surface of the powder particles and, in particular, cause interactions between them, which can promote a more impermeable and stable bond during subsequent sintering.

[0121] The suspension may be based on an organic solvent, preferably alcohol-based or more preferably water-based. For the interactions mentioned above with quartz glass, the polar nature of the aqueous phase may be advantageous.

[0122] In the preform state, the composite material consisting of a quartz glass phase, a silicon-containing phase, and a silicon carbide-containing phase is porous and can be modified by gas phase, especially by doping and reactive drying.

[0123] It should be considered that the molded body shrinks significantly during the final sintering in step d. of the process. Typically, the linear shrinkage is about 10%. Therefore, the preform must be larger than the sintered molded body. The sintered molded body is then further machined to obtain the final part. The sintered molded body has a near-net-shape.

[0124] This can be, for example, a solid, hollow, or layered body. The blank can be produced by casting the suspension into a mold. However, other processing methods for the suspension are also suitable, such as layer-by-layer application by dipping, spraying, brushing, applying with a scraper, transferring, laying, scraping, etc.

[0125] The preform is dried, resulting in a largely anhydrous molded body. However, as an inevitable consequence of its production, the preform contains a significant amount of hydroxyl groups. The preform is then typically sintered to form an impermeable, mechanoelastic molded body.

[0126] The method according to the invention may preferably include a method step in which the dried blank obtained from method step c is machined prior to sintering in method step d.

[0127] In step d. of the method, the sintering temperature must be selected such that the silicon-containing phase does not melt, but the highest possible density of the composite material is achieved through sintering. Suitable sintering parameters (sintering temperature, sintering time, and atmosphere) can be determined through simple experiments. Examples of suitable method conditions are described below.

[0128] The sintering process, step d, is carried out at a temperature preferably above or equal to 1300°C, more preferably above or equal to 1325°C, and even more preferably above or equal to 1350°C. The material becomes compressed, and the molded body shrinks, with a linear shrinkage of approximately 10%.

[0129] Method step c is carried out, particularly at temperatures below 1414°C, more preferably below 1400°C, and even more preferably below 1390°C, thereby preventing silicon from melting during the method according to the invention.

[0130] The duration of step d. depends on the temperature and the initial density of the preform. At 1390°C, 5 hours is sufficient for the slip-cast preform to achieve fully closed-cell porosity. At lower temperatures, step e. may take longer.

[0131] The sintering method step d is preferably carried out under atmospheric conditions, i.e., in air and at standard pressure.

[0132] After sintering, the preform made of quartz glass, silicon and silicon carbide particles produces a material with a significantly lower hydroxyl content than the material produced by sintering a preform consisting only of SiO2 particles.

[0133] At high temperatures, the surface of the silicon-containing phase can react with present hydroxyl groups and / or with water, for example, under the following conditions and reaction equations:

[0134] Si + 2OH → SiO₂ + H₂

[0135] Si + 2H₂O → SiO₂ + 2H₂

[0136] This reaction during the sintering of the molded body can serve as the basis for the subsequent properties of the composite material according to the invention:

[0137] During sintering, the water and hydroxyl groups present are consumed and converted into SiO2. Due to the slip casting production technology, the hydroxyl content in the sintered parts is surprisingly low, preferably below 30 ppm by weight. This results in a relatively high viscosity of the composite material.

[0138] The present invention also relates to the use of the composite material according to the invention for manufacturing components of processing chambers for wafer production and processing. Components according to the invention are wholly or partially composed of the composite material according to the invention. If a component is only partially composed of the composite material according to the invention, the material preferably forms at least a portion of the surface of the component. Due to the chemical composition of the composite material according to the invention, coatings made from this composite material are particularly suitable for quartz glass, i.e., for the production of quartz glass / composite material composite parts. The component, or at least the surface of the component, possesses the explained optical and structural properties.

[0139] The component according to the invention thus has, at least in the region, a quartz glass matrix with low porosity and finely distributed but encapsulated silicon-containing phase and encapsulated silicon carbide-containing phase. Even in the case of a thin layer with an extension of about 1 mm, the component according to the invention is opaque in the visible wavelength range, but otherwise largely possesses the typical chemical and mechanical properties of quartz glass.

[0140] In addition to applications requiring high heat absorption and uniform temperature distribution, components are also suitable for applications where high thermal and chemical stability and high resistance to corrosive gases and liquids are important. These requirements are typically present for components used in semiconductor manufacturing, optical devices, and chemical engineering.

[0141] The high emissivity of composite materials makes the components particularly suitable for heat treatment contexts where reproducible and uniform temperature distribution is important.

[0142] Therefore, according to the present invention, the use of the component in a processing chamber in which a semiconductor wafer is processed into a chip is provided. Specifically, the component is used in a system in which high-temperature processes (e.g., CVD, ALD, epitaxy, or annealing) are performed.

[0143] Another intended use of the invention is for components that heat by radiation (lamp) and for components intended to block thermal radiation.

[0144] The component according to the invention is provided as a component for use in a processing chamber during oxidation or heat treatment, specifically in rapid thermal processing (RTP), in epitaxy, or in chemical vapor deposition.

[0145] Components can take the form of containers, bowls, shells, solid bodies, or hollow bodies that are extended or curved. In simpler cases, components are designed as plates, rings, flanges, domes, crucibles, or solid or hollow cylinders. Composite materials can be in the form of solids or layers. Detailed Implementation

[0146] Exemplary Implementation :

[0147] Samples 1 (L7), 2 (L8), 3 (L9), 4 (L10), 5 (L11), 6 (L17), 7 (L18), 8 (L19), 9 (L2), 10 (L3), 11 (Reference A), 12 (Reference B), and 13 (Reference C) were produced as follows:

[0148] An aqueous suspension of ground quartz glass particles was used as the starting material for the production of laboratory samples. The suspension had a solids content of 78% by weight and a particle size distribution with a D90 value of 45 μm.

[0149] Using a laboratory stirrer, Si powder and SiC powder are added to the suspension according to the proportions given in the table (the values ​​are related to the amount of SiO2).

[0150] The D10, D50, and D90 values ​​of the particle size distribution of Si powder and SiC powder are as follows:

[0151] Si powder: D10=2.5µm, D50=5.3µm, D90=9.8µm

[0152] SiC powder 1: D10=2.9μm, D50=5.4μm, D90=9.6μm

[0153] SiC powder 2: D10=1.7μm, D50=8.2μm, D90=16.8μm

[0154] Particle size was measured by laser diffraction using a Mastersizer 3000 from Malvern.

[0155] Powder 1 is mainly composed of α-SiC (polymorph 6H), while powder 2 is β-SiC (polymorph 3C). The crystal structure was determined using X-ray diffraction.

[0156] To produce samples, the mixed suspension is poured into a cylindrical mold with a porous bottom. Through this mold, some water is removed from the suspension until a dimensionally stable blank is formed.

[0157] After the formation process is completed, the green body is dried in a drying oven at 60°C until the residual moisture content is <1%.

[0158] The dried green body is then sintered in an electric heating furnace using the sintering parameters given in the table.

[0159] Optical and density measurements were performed on samples cut from the center of the sintered cylindrical mold.

[0160] Color measurements are performed on a cross-sectional area that is bisected along the axis of the sintered molded body.

[0161] surface

[0162]

[0163]

[0164] Figure 1 shows the hemispherical reflection in the visible range and the IR range of a 3 mm thick composite material containing silicon carbide phases with varying amounts of α-silicon carbide, without the silicon carbide phase.

[0165] Figure 2 shows the hemispherical reflection in the visible range and the IR range of a 3 mm thick composite material containing a silicon carbide phase but without a silicon carbide phase and containing silicon carbide phases with different amounts of β-silicon carbide.

[0166] Figure 3 shows the hemispherical transmission in the visible range and the hemispherical reflection in the IR range of a 3 mm thick composite material containing silicon carbide phases with varying amounts of α-silicon carbide but without the silicon carbide phase.

[0167] Figure 4 shows the hemispherical transmission in the visible range and the hemispherical reflection in the IR range of a 3 mm thick composite material containing silicon carbide phases with varying amounts of β-silicon carbide but without the silicon carbide phase.

[0168] Figure 5 shows the calculated absorption in the visible range and the calculated absorption in the IR range for a 3 mm thick composite material containing a silicon carbide phase but without a silicon carbide phase and containing different amounts of α-silicon carbide.

[0169] Figure 6 shows the calculated absorption in the visible range and the calculated absorption in the IR range for a 3 mm thick composite material containing a silicon carbide phase but not containing a silicon carbide phase and containing different amounts of β-silicon carbide.

[0170] Figures 1 and 2 show that, compared with the composite material produced according to EP 3 068 739 A without the silicon carbide phase, the composite material according to the present invention exhibits reduced hemispherical reflection at wavelengths above about 1000 nm.

[0171] Figures 3 and 4 show that, compared with the composite material produced according to EP 3 068 739 A without the silicon carbide phase, the composite material according to the present invention does not have any significant transmission in the visible and IR ranges.

[0172] Figures 5 and 6 show that, compared with the composite material produced according to EP 3 068 739 A without the silicon carbide phase, the composite material according to the present invention exhibits high absorption at wavelengths above approximately 1000 nm.

[0173] Figures 7 to 9 show the emissivity of the composite material according to the invention at elevated temperatures at different temperatures of 500°C, 750°C, and 1000°C and at different proportions of α-silicon carbide in the composite material.

[0174] Figures 7 to 9 show that the emissivity of the composite material according to the present invention increases with increasing temperature in the wavelength range of 1 μm to 5 μm, reaching up to 0.8 at 1000 °C. The temperature-dependent fluctuation of emissivity decreases with increasing silicon carbide content of the composite material.

[0175] The absorptivity of the composite material according to the present invention at high temperatures was determined by measuring emissivity. The temperature behavior of the absorptivity in the near-infrared at a wavelength of 1.5 μm for three samples with different SiC concentrations is shown in Figure 12 and Table 2 below.

[0176] Figure 10 shows a SEM image of a cross-sectional region of the composite material according to the invention, having been sintered at 1390 °C for 5 hours and containing 2.5 wt% carbon and 2.5 wt% silicon carbide. P represents pores, and Si and SiC represent Si particles and SiC particles embedded in the quartz glass matrix, respectively.

[0177] Figure 11 shows a SEM image of a cross-sectional region of the composite material according to the invention, having been sintered at 1390 °C for 10 hours and containing 2.5 wt% carbon and 2.5 wt% silicon carbide. Pores are not identifiable in the image; Si and SiC represent Si particles and SiC particles embedded in the quartz glass matrix, respectively.

[0178] Figures 10 and 11 show the composite material according to the invention having low porosity.

[0179] Table 2

[0180]

Claims

1. A composite material having a matrix made of quartz glass, wherein regions containing a silicon phase and regions containing a silicon carbide phase are embedded in the matrix.

2. The composite material according to claim 1, characterized in that, The 3mm thick disk of the composite material has an absorption of more than 50% at 1500nm.

3. The composite material according to claim 1 or 2, characterized in that, The 3mm thick disk of the composite material has less than 50% hemispherical reflection at 1500nm.

4. The composite material according to any one of claims 1 to 3, characterized in that, The 3mm thick disk of the composite material has a transmittance of less than 1%, more preferably less than 0.8%, and even more preferably less than 0.6% in the wavelength range of 0.4μm to 2.5μm.

5. The composite material according to any one of claims 1 to 4, characterized in that, The 3mm disk of the composite material exhibits an absorption capacity / emissivity change of less than 0.3, more preferably less than 0.2, and particularly preferably less than 0.1 at a wavelength of 1.5μm between room temperature (20°C) and 1000°C.

6. The composite material according to any one of claims 1 to 5, characterized in that, The weight percentage of the silicon-containing phase, in each case based on the matrix made of quartz glass, is from 0.25% to 10% by weight, more preferably from 0.5% to 9% by weight, even more preferably from 1% to 8% by weight, even more preferably from 1.5% to 7% by weight, even more preferably from 2% to 6% by weight, even more preferably from 2.5% to 5% by weight.

7. The composite material according to any one of claims 1 to 6, characterized in that, The weight percentage of the silicon carbide phase, based on the matrix made of quartz glass, is in each case 0.25 wt% to 20 wt%, more preferably 0.25 wt% to 15 wt%, more preferably 0.25 wt% to 10 wt%, more preferably 0.5 wt% to 9 wt%, even more preferably 1 wt% to 8 wt%, even more preferably 1.5 wt% to 7 wt%, even more preferably 2 wt% to 6 wt%, even more preferably 2.5 wt% to 5 wt%.

8. The composite material according to any one of claims 1 to 7, characterized in that, The particle size distribution d90 of the silicon particles is less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm, and / or the particle size distribution d90 of the silicon carbide particles is less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm.

9. The composite material according to any one of claims 1 to 8, characterized in that, The composite material contains less than 100 ppm, more preferably less than 50 ppm, and even more preferably less than 25 ppm of metallic impurities, which are determined by inductively coupled plasma optical emission spectroscopy.

10. The composite material according to any one of claims 1 to 9, characterized in that, The composite material has a porosity of less than 2%, more preferably less than 1.5%, and even more preferably less than 1%, wherein the porosity is defined as the pore volume based on the total volume of the composite material.

11. The composite material according to any one of claims 1 to 10, characterized in that, The composite material is carbon-free.

12. A method for producing a composite material according to any one of claims 1 to 11, characterized in that... The following steps are: a. providing a mixture comprising amorphous quartz glass particles, silicon-containing powder, and silicon carbide-containing powder as a suspension; b. forming a molded body from the suspension generated in step a. by a slip casting method to obtain a preform; c. Dry the green body; and d. Sinter the dried green body obtained from step c.

13. The method according to claim 12, characterized in that, The quartz glass particles in the suspension have a particle size distribution having a d90 value of less than 100 μm, more preferably less than 75 μm, and even more preferably less than 50 μm, as determined by laser diffraction according to ISO 2019:13320 in each case.

14. The method according to claim 12 or 13, characterized in that, The solid content in the aqueous suspension composed of quartz glass particles is more than 50% by weight, more preferably more than 65% by weight, and even more preferably more than 75% by weight.

15. Use of a composite material according to any one of claims 1 to 11 for producing components for a processing chamber in which semiconductor crystals are processed into chips, systems for which high-temperature processes are performed, components for heating by radiation, and parts for blocking thermal radiation.

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