KR102557847B1 - Plasma resistant glass and manufacturing method the same - Google Patents

Abstract

Embodiments of the present invention relate to a plasma glass and a method for manufacturing the same, and a technical problem to be solved is to provide a plasma glass with improved plasma resistance and a method for manufacturing the same. To this end, the present invention provides a plasma-resistant glass comprising 40 to 75 mol% of SiO ₂ , 5 to 20 mol% of Al ₂ O ₃ , 10 to 40 mol% of MgO, and 0.01 to 10 mol% of MgF ₂ and a manufacturing method thereof.

Description

Plasma resistant glass and manufacturing method thereof {Plasma resistant glass and manufacturing method the same}

Embodiments of the present invention relate to plasma-resistant glass and a manufacturing method thereof.

A plasma etching process is applied in the manufacture of semiconductors and/or displays. As the nano process is recently applied, the difficulty of etching increases and the internal parts of the process chamber exposed to the high-density plasma environment are oxide-based ceramics such as alumina (Al ₂ O ₃ ) and yttria (Y ₂ O ₃ ) having corrosion resistance. Mainly used.

When a polycrystalline material is exposed to a high-density plasma etching environment using a fluorine-based gas for a long period of time, particles are eliminated due to local erosion, thereby increasing the probability of generating contaminant particles. This causes defects in semiconductors/displays and adversely affects production yield.

The above-described information disclosed in the background art of the present invention is only for improving understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

An object to be solved according to an embodiment of the present invention is to provide a plasma glass with improved plasma resistance and a manufacturing method thereof.

Method for producing a plasma glass according to an embodiment of the present invention comprises the steps of preparing a plasma glass raw material by mixing SiO ₂ powder, Al ₂ O ₃ powder, MgO powder and MgF ₂ powder; Melting the plasma glass raw material; Slowly cooling the molten product at a temperature higher than the glass transition temperature (Tg); furnace-cooling the slowly cooled product to room temperature; and obtaining a furnace-cooled plasma glass, wherein the obtained plasma glass may include 40 to 75 mol% of SiO ₂ , 5 to 20 mol% of Al ₂ O ₃ , 10 to 40 mol% of MgO, and 0.01 to 10 mol% of MgF ₂ .

The MgO and the MgF ₂ may have a molar ratio of 95:5 to 80:20.

The glass transition temperature (T _g ) of the obtained plasma glass may be 700°C to 800°C.

The softening point (T _dsp ) of the obtained plasma glass may be 750°C to 850°C.

The obtained plasma-resistant glass is a glass used in a mixed plasma environment of fluorine and argon (Ar), and the obtained plasma-resistant glass has an etch rate of less than 15 nm/min with respect to a mixed plasma of fluorine and argon. It may have plasma resistance characteristics lower than.

The melting step may be performed at a temperature of 1300 ° C to 1650 ° C.

The slow cooling step may be performed at a temperature of 700 ° C to 900 ° C.

The plasma-resistant glass according to an embodiment of the present invention may include 40 to 75 mol% of SiO ₂ , 5 to 20 mol% of Al ₂ O ₃ , 10 to 40 mol% of MgO, and 0.01 to 10 mol% of MgF ₂ .

The plasma-resistant glass may be an internal part of a process chamber for manufacturing a semiconductor.

The internal parts include a focus ring, an edge ring, a cover ting, a ring shower, an insulator, an EPD window, an electrode, a view port, an inner shutter, an electrostatic chuck, a heater, a chamber liner, a shower head, a chemical vapor deposition (CVD) boat ( boat), wall liner, shield, cold pad, source head, outer liner, deposition shield, upper liner, exhaust plate, and mask frame.

Embodiments of the present invention provide a plasma glass with improved plasma resistance and a manufacturing method thereof. For example, the plasma-resistant glass according to an embodiment of the present invention may be a glass used in a mixed plasma environment of fluorine and argon (Ar). In this case, the plasma glass may have a mixed plasma of fluorine and argon. The etching rate (nm / min) may be lower than about 15. In addition, the plasma glass according to the embodiment of the present invention has a hardness (Gpa) of about 6.5 to about 7.5, a dielectric constant (F / m) of about 4 to about 6, and a density (g / cm ³ ) By having about 2 to about 3, it can be suitably used in conventional plasma etching equipment.

1 is a flowchart illustrating a method for manufacturing a plasma glass resistant according to an embodiment of the present invention.
Figure 2 is a table showing the composition ratio for the manufacture of plasma glass according to an embodiment of the present invention.
3 is a photograph showing a plasma glass according to an embodiment of the present invention.
Figure 4 is a table showing various characteristics of the plasma glass according to an embodiment of the present invention.
5 is a graph showing amorphous pattern measurement results for plasma-resistant glass according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified in many different forms, and the scope of the present invention is not limited to the following examples. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the spirit of the invention to those skilled in the art.

As used herein, the term "and/or" includes any one and all combinations of one or more of the listed items. Also, terms used in this specification are used to describe specific embodiments and are not intended to limit the present invention. As used herein, the singular form may include the plural form unless the context clearly indicates otherwise. Also, when used herein, “comprise, include” and/or “comprising, including” specifies the presence of the recited shapes, numbers, steps, operations, elements, elements and/or groups thereof, and does not exclude the presence or addition of one or more other shapes, numbers, operations, elements, elements and/or groups.

In this specification, terms such as first and second are used to describe various members, components, regions, layers, and/or portions, but these members, components, regions, layers, and/or portions are not limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first member, component, region, layer or section described in detail below may refer to a second member, component, region, layer or section without departing from the teachings of the present invention.

Referring to Figure 1, there is shown a flow chart for a method of manufacturing a plasma glass according to an embodiment of the present invention.

As shown in FIG. 1 , the method for manufacturing a plasma-resistant glass according to an embodiment of the present invention may include a plasma-resistant raw material preparation step (S1), a melting step (S2), a slow cooling step (S3), a furnace cooling step (S4), and a plasma-resistant glass obtaining step (S5).

In the plasma glass raw material preparation step (S1), the plasma glass raw material may be prepared by mixing SiO ₂ powder, Al ₂ O ₃ powder, MgO powder, and MgF ₂ powder.

In some examples, Al ₂ O ₃ may include, for example, Al(OH) ₃ as a precursor, MgO may include, for example, Mg(OH) ₂ as a precursor, and MgF ₂ may include, as a precursor, a solution formed by the reaction of MgCl ₂ and anhydrous HF, for example.

In the melting step (S2), the plasma glass raw material may be melted.

In some examples, the melting step may be performed at a temperature of about 1300° C. to about 1650° C. in an oxidizing atmosphere.

In the slow cooling step (S3), the molten plasma glass raw material may be slowly cooled or annealed.

In some examples, the annealing or annealing step may be performed at a temperature of about 700°C to about 900°C in an oxidizing atmosphere.

In the furnace cooling step (S4), the slow-cooled plasma glass raw material may be gradually cooled.

In some instances, the furnace cold may be performed by allowing the temperature in the furnace to naturally reach room temperature (eg, 20° C.).

In the plasma-resistant glass obtaining step (S5), a furnace-cooled product, that is, plasma-resistant glass manufactured according to an embodiment of the present invention may be obtained.

In some examples, the glass transition temperature (Tg) of the obtained plasma glass may be approximately 700°C to approximately 800°C.

In some examples, the softening point (Tdsp) of the plasma-resistant glass obtained may be between approximately 700°C and approximately 800°C.

In some examples, the obtained plasma-resistant glass may include from about 40% to about 75% SiO ₂ , from about 5% to about 20% Al ₂ O ₃ , from about 10% to about 40% MgO, and from about 0.01% to about 10% MgF ₂ mol.

In some examples, MgO and MgF ₂ in the obtained plasma-resistant glass may have a molar ratio of 95:5 to 80:20.

In some examples, the obtained plasma-resistant glass is a glass used in a mixed plasma environment of fluorine and argon (Ar), and the obtained plasma-resistant glass has an etch rate of about 5 nm / min to about 15 nm / min with respect to the mixed plasma of fluorine and argon.

Referring to FIG. 2, a table of composition ratios for the manufacture of plasma-resistant glass according to an embodiment of the present invention is shown.

Example 1 (MASF 9505)

In the plasma-resistant glass raw material preparation step (S1), 59.267 mol% of SiO ₂ powder, 10.305 mol% of Al ₂ O ₃ powder, 28.907 mol% of MgO powder, and 1.521 mol% of MgF ₂ powder were mixed to prepare a plasma-resistant glass raw material.

As an example, the total amount of chemical components was placed in a weight of 600 g, and the plasma glass raw material was mixed for about 1 hour using a zirconia ball milling method. In some examples, the plasma glass material was dry mixed with 600 g of material:1800 g of zirconia balls (weight ratio 1:3), followed by drying for 24 hours. As another example, the total amount of the chemical components may be placed in a weight of 600 g, and the plasma glass raw material may be mixed for approximately 1 hour using a zirconia ball milling method. In some examples, the plasma glass material may be wet mixed with 600 g of raw material: 2400 g of ethanol: 5400 g of zirconia balls (weight ratio 1:4:9) and then dried for 24 hours.

In the melting step (S2), the plasma glass raw material mixed in the dry mixing method or the wet mixing method was heated at a rate of 10° C./min until reaching a temperature of 1400° C. using a Super Catalo, and maintained at the temperature of 1400° C. for about 2 hours and 30 minutes.

In the slow cooling step (S3), the molten plasma-resistant glass was slowly cooled until it reached a temperature of 820°C, and maintained at the temperature of 820°C for about 3 hours.

In the furnace cooling step (S4), the slowly cooled plasma glass was naturally cooled until it reached room temperature (eg, 20° C.).

Thereafter, in the plasma glass obtaining step (S5), a furnace-cooled plasma glass containing MgO and MgF ₂ was obtained. Here, the molar ratio of MgO and MgF ₂ may be approximately 95:5.

Example 2 (MASF9010)

In the plasma-resistant glass raw material preparation step (S1), 59.267 mol% of SiO ₂ powder, 10.305 mol% of Al ₂ O ₃ powder, 27.385 mol% of MgO powder, and 3.043 mol% of MgF ₂ powder were mixed to prepare a plasma-resistant glass raw material. Other steps S2 to S5 are similar or the same as in Example 1. Here, the molar ratio of MgO and MgF ₂ in the obtained plasma-resistant glass may be approximately 90:10.

Example 3 (MASF8515)

In the plasma-resistant glass raw material preparation step (S1), 59.267 mol% of SiO ₂ powder, 10.305 mol% of Al ₂ O ₃ powder, 25.864 mol% of MgO powder, and 4.564 mol% of MgF ₂ powder were mixed to prepare a plasma-resistant glass raw material. Other steps S2 to S5 are similar or identical to those in Example 1. Here, the molar ratio of MgO and MgF ₂ in the obtained plasma-resistant glass may be approximately 85:15.

Example 4 (MASF8020)

In the plasma-resistant glass raw material preparation step (S1), 59.267 mol% of SiO ₂ powder, 10.305 mol% of Al ₂ O ₃ powder, 24.342 mol% of MgO powder, and 6.086 mol% of MgF ₂ powder were mixed to prepare a plasma-resistant glass raw material. Other steps S2 to S5 are similar or the same as in Example 1. Here, the molar ratio of MgO and MgF ₂ in the obtained plasma-resistant glass may be approximately 80:20.

Comparative Example (MAS)

In the plasma-resistant glass raw material preparation step (S1), 59.267 mol% of SiO ₂ powder, 10.305 mol% of Al ₂ O ₃ powder, and 30.428 mol% of MgO powder were mixed to prepare a plasma-resistant glass raw material. Other steps S2 to S5 are similar or the same as in Example 1. Here, there is no MgF ₂ in the obtained plasma-resistant glass.

Referring to Figure 3, a picture of the plasma glass according to an embodiment of the present invention is shown. Here, MAS is a comparative example, MASF9505 is Example 1, MASF9010 is Example 2, MASF8515 is Example 3, and MASF 8020 is a picture of the plasma glass manufactured according to Example 4. As shown in FIG. 3, all of the plasma-resistant glasses according to Comparative Example and Examples 1 to 4 were transparent and did not have a specific color (eg, yellow or white).

Referring to FIG. 4, a table of various characteristics of the plasma glass according to an embodiment of the present invention is shown.

First, the thermal properties (T _g , T _{c1, C2} and T _l ) of the plasma glass were measured. After placing the completed plasma glass in Labsys evo, the temperature was increased to 1400 °C at a rate of 10 °C/min, where argon gas (40-50 cc/min) was used.

The glass transition temperature (T _g ) of the plasma glass prepared in Example 1 (MASF9505) was approximately 774.4 ° C, the first inflection point temperature (T _c1 ) was approximately 1034.1 ° C, the second inflection point temperature (T _c2 ) was approximately 1100.2 ° C, and the liquidus temperature (T _l ) was measured to be 1366.1 ° C.

The glass transition temperature (T _g ) of the plasma glass prepared in Example 2 (MASF9010) was approximately 764.4 ° C, the first inflection point temperature (T _c1 ) was approximately 1026.3 ° C, the second inflection point temperature (T _c2 ) was approximately 1060.7 ° C, and the liquidus temperature (T _l ) was measured to be 1362.9 ° C.

The glass transition temperature (T _g ) of the plasma glass prepared in Example 3 (MASF8515) was approximately 729.6 ° C, the first inflection point temperature (T _c1 ) was approximately 996.6 ° C, the second inflection point temperature (T _c2 ) was approximately 1030.3 ° C, and the liquidus temperature (T _l ) was measured to be 1356.5 ° C.

The glass transition temperature (T _g ) of the plasma glass prepared in Example 4 (MASF8020) was approximately 734.0 ° C, the first inflection point temperature (T _c1 ) was approximately 1027.8 ° C, the second inflection point temperature (T _c2 ) was approximately 1063.3 ° C, and the liquidus temperature (T _l ) was measured to be 1358.6 ° C.

The glass transition temperature (T _g ) of the plasma glass prepared in the comparative example (MAS) was approximately 799.4 ° C, the first inflection point temperature (T _c1 ) was approximately 1056.6 ° C, the secondary inflection point temperature (T _c2 ) was approximately 1253.6 ° C, and the liquidus temperature (T _l ) was measured as 1368.6 ° C.

In this way, T _g , T _{c1, C2} and T _l generally decreased as the content of MgF ₂ increased, but when the ratio of MgO:MgF ₃ was approximately 80:20, T _g , T _c1,c2 and T _l increased again.

Next, the thermal expansion coefficient (CTE: × 10 ^-6 m/(m ℃)), glass transition temperature (Tg), and softening point (T _dsp ) of the plasma glass were measured. After placing the completed plasma glass in Labsys evo, the temperature was increased to 1000 °C at a rate of 10 °C/min, and no gas was used at this time.

The plasma-resistant glass prepared in Example 1 (MASF9505) had a CTE of approximately 4.68, a glass transition temperature (T _g ) of approximately 774.4 °C, and a softening point (T _dsp ) of approximately 827.5 °C.

The CTE of the plasma glass prepared in Example 2 (MASF9010) was approximately 4.74, the glass transition temperature (T _g ) was approximately 764.4 ° C, and the softening point (T _dsp ) was approximately 811.4 ° C.

The CTE of the plasma glass prepared in Example 3 (MASF8515) was approximately 5.58, the glass transition temperature (T _g ) was approximately 729.6 ° C, and the softening point (T _dsp ) was approximately 771.8 ° C.

The plasma glass prepared in Example 4 (MASF8020) had a CTE of approximately 5.63, a glass transition temperature (T _g ) of approximately 734.0 °C, and a softening point (T _dsp ) of approximately 784.1 °C.

The CTE of the plasma glass prepared according to the comparative example (MAS) was approximately 5.44, the glass transition temperature (T _g ) was approximately 799.4 °C, and the softening point (T _dsp ) was approximately 837.0 °C.

In this way, CTE, T _dsp , and T _g generally decreased as the content of MgF ₂ increased, but the content of MgF ₃ increased again above a certain value.

Next, the hardness (GPa) of the plasma glass was measured. After placing the completed plasma glass on the HMV and micro hardness tester (SHIMADZU), it was measured 5 times with a force of 300 g.f (2.94199 N) and the average value was taken.

The hardness (GPa) of the finished plasma glass was measured to be approximately 6.9 for Example 1 (MASF9505), approximately 6.3 for Example 2 (MASF9010), approximately 6.9 for Example 3, approximately 6.9 for Example 4, and approximately 6.9 for Comparative Example (MAS).

In this way, there was generally no change in hardness with an increase in the content of MgF ₂ . For reference, the hardness of quartz is approximately 20, the hardness of synthetic quartz is approximately 8.23, the hardness of sapphire is approximately 17.9, and the hardness of the Al ₂ O ₂ coating layer is approximately 17.1.

Next, the dielectric constant (F/m) of the plasma glass was measured. It was measured for 1 minute at a frequency of 1 MHz, and the average value was obtained after 5 measurements.

The dielectric constant (F/m) of the finished plasma-resistant glass is approximately 4.859 for Example 1 (MASF9505), approximately 4.810 for Example 2 (MASF9010), approximately 5.161 for Example 3, approximately 5.162 for Example 4, and approximately 4.714 for Comparative Example (MAS).

In this way, in general, as the content of MgF ₂ increases, the dielectric constant value increases.

Next, the etching rate (nm/min) of plasma-resistant glass was measured. After the completed plasma glass was placed on the surfcorder ET3000 (Kosaka laboratory Ltd., Japan), the average value was measured after three measurements. At this time, the etching conditions were as follows.

RF power(W) : 600

RF power, bias(W) : 150

_CF4 (SCCM): 30

Ar(SCCM) : 10

O2(SCCM) : 5

Pressure(mTorr) : 10

Time(min) : 60

The etching rate (nm/min) of the plasma-resistant glass was measured to be approximately 7.6 for Example 1 (MASF9505), approximately 14.12 for Example 2 (MASF9010), approximately 11.09 for Example 3, approximately 12.03 for Example 4, and approximately 9.49 for Comparative Example (MAS).

In this way, the etch rate generally decreased as the content of MgF ₂ increased, but in Example 1 (MASF9505), the etch rate was particularly decreased. For reference, the etching rate of sapphire is approximately 29.37, the etching rate of quartz is approximately 214.01, and the etching rate of synthetic quartz is approximately 212.49.

Next, the density (g/cm ³ ) of the plasma glass was measured. The density of the finished plasma glass was measured by Archimedes/Pycnometer.

The density (g/cm ³ ) of the plasma-resistant glass was measured to be approximately 2.59 for Example 1 (MASF9505), approximately 2.59 for Example 2 (MASF9010), approximately 2.59 for Example 3 (MASF8515), approximately 2.59 for Example 4 (MASF8020), and approximately 2.6 for Comparative Example (MAS).

In this way, the density was generally similar regardless of the increase in the content of furnace MgF ₂ .

Referring to FIG. 5, there is shown a graph of amorphous pattern measurement results for the plasma glass according to an embodiment of the present invention. In FIG. 5, the X axis is 2θ (deg.), the Y axis is intensity (a.u.), and the crystal structure of the plasma-resistant glass prepared according to Examples and Comparative Examples of the present invention at a rate of 10 ° / min between approximately 10 ° and 80 ° was measured by XRD (X-ray diffraction) equipment. As shown in FIG. 5, all of the plasma-resistant glasses prepared according to Examples 1 to 4 and Comparative Example had a peak value between 20 ° and 30 ° in 2 theta value, so that they did not have a specific crystal structure, that is, it was confirmed that they were amorphous structures.

In this way, when the plasma glass contains MgF ₂ , it can be seen that the glass transition temperature (T _g ) and softening point (T _dsp ) are lowered. Therefore, since the viscosity and melting point of the plasma glass containing MgF ₂ are reduced, a low melting point plasma glass that is easy to process is eventually provided.

In addition, when the plasma glass contains MgF ₂ , plasma resistance is improved. For example, when the plasma glass is exposed to a CF ₄ -based plasma environment, a fluorine compound layer is formed on the plasma glass by reacting with each other. Such a fluorine compound layer reduces the etching rate. However, in the embodiment of the present invention, since the plasma glass already contains fluorine (F) element, when the plasma glass is exposed to a CF ₄ -based plasma environment, a fluorine compound layer is formed more quickly and thickly on the surface of the plasma glass, and thus the plasma resistance can be further improved. Here, when MgO and MgF ₂ have a molar ratio of a predetermined ratio (eg, 95:5 to 80:20), plasma resistance may be further improved.

In addition, plasma-resistant glass containing MgO and MgF ₂ has hardness, dielectric constant, and density that are matched to existing parts in plasma etching equipment without any heterogeneity, so it can be easily adopted in existing plasma etching equipment.

As an example, the above-described plasma-resistant glass may be an internal part of a process chamber for manufacturing a semiconductor or display. For example, internal parts include a focus ring, an edge ring, a cover ting, a ring shower, an insulator, an EPD window, an electrode, a view port, an inner shutter, an electrostatic chuck, a heater, a chamber liner, a shower head, and a chemical vapor deposition (CVD) It may include a boat, wall liner, shield, cold pad, source head, outer liner, deposition shield, upper liner, exhaust plate and/or mask frame. Here, the above-described internal parts may be manufactured through various methods such as melting, compression molding, and compression sintering of the above-described plasma glass powder.

What has been described above is only one embodiment for carrying out the plasma-resistant glass and its manufacturing method according to the present invention, and the present invention is not limited to the above-described embodiments, and as claimed in the following claims, anyone with ordinary knowledge in the field to which the present invention belongs will have the technical spirit of the present invention to the extent that various changes can be made without departing from the gist of the present invention.

Claims (14)

Preparing a plasma glass raw material by mixing SiO ₂ powder, Al ₂ O ₃ powder, MgO powder, and MgF ₂ powder;
Melting the plasma glass raw material;
Slowly cooling the molten product at a temperature higher than the glass transition temperature (Tg);
furnace-cooling the slowly cooled product to room temperature; and
Obtaining a furnace-cooled plasma glass,
The obtained plasma glass contains 40 to 75 mol% of SiO ₂ , 5 to 20 mol% of Al ₂ O ₃ , 10 to 40 mol% of MgO and 0.01 to 10 mol% of MgF ₂ . According to claim 1,
The MgO and the MgF ₂ have a molar ratio of 95: 5 to 80: 20, a method for producing a plasma glass. According to claim 1,
The glass transition temperature (T _g ) of the obtained plasma glass is 700 ℃ ~ 800 ℃, the method of producing a plasma glass. According to claim 1,
The softening point (T _dsp ) of the obtained plasma glass is 750 ° C to 850 ° C, a method for producing a plasma glass. According to claim 1,
The obtained plasma glass is a glass used in a mixed plasma environment of fluorine and argon (Ar), and the obtained plasma glass has an etch rate lower than 15 nm / min for a mixed plasma of fluorine and argon. A method for producing a plasma glass having resistance to plasma characteristics. According to claim 1,
The melting step is performed at a temperature of 1300 ° C to 1650 ° C, a method for producing a plasma glass. According to claim 1,
The slow cooling step is performed at a temperature of 700 ° C to 900 ° C, a method for producing a plasma glass.
40 to 75 mol% of SiO ₂ , 5 to 20 mol% of Al ₂ O ₃ , 10 to 40 mol% of MgO, and 0.01 to 10 mol% of MgF ₂ , plasma-resistant glass. According to claim 8,
The MgO and the MgF ₂ have a molar ratio of 95:5 to 80:20, plasma glass. According to claim 8,
The glass transition temperature (T _g ) of the plasma glass is 700 ℃ ~ 800 ℃, the plasma glass. According to claim 8,
The softening point (T _dsp ) of the plasma glass is 750 ℃ ~ 850 ℃, the plasma glass. According to claim 8,
The plasma glass is a glass used in a mixed plasma environment of fluorine and argon (Ar), and the plasma glass has an etch rate lower than 15 nm/min with respect to a mixed plasma of fluorine and argon. Plasma glass having resistance to plasma characteristics. According to claim 8,
The plasma glass is an internal part of a process chamber for semiconductor manufacturing, plasma glass. According to claim 13,
The internal parts include a focus ring, an edge ring, a cover ting, a ring shower, an insulator, an EPD window, an electrode, a view port, an inner shutter, an electrostatic chuck, a heater, a chamber liner, a shower head, a chemical vapor deposition (CVD) boat ( boat), wall liner, shield, cold pad, source head, outer liner, deposition shield, upper liner, exhaust plate, and mask frame. Plasma-resistant glass.

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