JP2023524523A - Method for manufacturing aluminum alloy plate for vacuum chamber member - Google Patents

Abstract

Herein, (a) Mg 0.80%-1.05%, Si 0.70%-1.0%, Mn 0.70%-0.90%, Fe max 0.20%, Zn max 0.08% Cu, maximum 0.05% Cr, maximum 0.03% Cr, maximum 0.06% Ti, unavoidable impurities, and the balance aluminum (% by weight). (b) homogenizing the rolling feed at a temperature in the range of 550-595° C.; (d) solution heat treating (“SHT”) the hot rolled plate at a temperature in the range of 540-590° C.; (f) drawing the cooled SHT plate to obtain a permanent elongation of 1-5%; and (g) artificially aging the drawn plate. A method for manufacturing an aluminum alloy plate for [Selection figure] None

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of, and priority to, European Patent Application No. 20179258.7 filed June 10, 2020, the entire contents of which are hereby incorporated by reference. incorporated.

The present invention provides equipment for manufacturing semiconductor devices and liquid crystal devices, for example, vacuum chamber members such as CVD equipment, PVD equipment, ion implantation equipment, sputtering equipment, and dry etching equipment, and the inside of the vacuum chamber The present invention relates to a method for manufacturing an aluminum alloy plate of Al--Mg--Si series alloys (also known as 6XXX series aluminum alloys) to form a member to be disposed. The present invention further relates to a method for manufacturing a vacuum chamber member from an Al--Mg--Si based alloy plate. The invention further relates to a method for manufacturing valves and total assemblies from Al--Mg--Si based alloy plates.

Halogen-containing reactive gases, etching gases, and corrosive gases as cleaning gases are used in equipment for manufacturing semiconductor devices and liquid crystal devices, such as CVD equipment, PVD equipment, ion implantation equipment, sputtering equipment, and It is supplied to a vacuum chamber such as a dry etching device. Therefore, the vacuum chamber must have corrosion resistance to corrosive gases (hereinafter referred to as "corrosive gas resistance"). Since halogen plasma is often generated in the vacuum chamber, resistance to plasma (hereinafter referred to as "plasma resistance") is also important. In recent years, aluminum materials and aluminum alloy materials have been used to form members of vacuum chambers because of their light weight and excellent thermal conductivity. Since aluminum and aluminum alloy materials are not sufficient in corrosive gas resistance and plasma resistance, various surface quality improvement techniques have been proposed to improve these properties. However, many of these properties are still insufficient, and further improvements in these properties are desired. It has been found that coating an aluminum material or an aluminum alloy material with an anodized film having high hardness is effective in improving plasma resistance. A hard anodized film has resistance to wear of the member by plasma having high physical energy, and for this reason, plasma resistance can be improved. Vacuum chamber members also require sufficiently high mechanical strength, elongation, and color uniformity after anodization, as well as high breakdown voltage.

US patent document US-2012/0325381-A1 discloses a process for producing blocks of aluminum at least 250 mm thick designed for producing parts for vacuum chambers, the method comprising any 6XXX series aluminum casting an alloy ingot, optionally homogenizing the cast ingot, performing a solution heat treatment directly on the cast ingot, and optionally homogenizing the ingot; It involves quenching the ingot, subjecting the quenched ingot to stress relief annealing by cold pressing, followed by artificial aging to the T652 condition. A key element of the disclosed process is that the mass is not hot or cold worked to reduce its thickness prior to solution heat treatment. The resulting plate material is a so-called "cast plate". A drawback of cast plates is that in many cases, in the post-solidification eutectic state, unavoidable phases caused by mixing and precipitation at the grain boundaries of elements such as iron, manganese, magnesium, and silicon are dissipated during homogenization and solution treatment. It cannot be completely dissolved in subsequent processing steps such as heat treatment and remains as crack initiation sites, resulting in reduced mechanical properties (e.g., tensile strength, elongation, toughness, and other properties). be significantly degraded or left as a site for localized corrosion (e.g. pitting), or even detrimental to final treatments such as anodizing, which are particularly relevant to vacuum chamber components; is. Any oxide layer present within the cast alloy also remains in its original form, which also results in reduced mechanical properties. Compared to rolled plate, cast plate can be produced cost-effectively because the as-cast microstructure is substantially preserved, and can be strongly dependent on local cooling rates during the casting operation. As such, there is much more variability in mechanical properties that vary from test site to test site, making cast plates less suitable for many important applications.

1 is an optical microscopy image of a sample for phase and grain analysis of an aluminum alloy material described herein.

As will be understood hereinafter, unless otherwise specified, aluminum alloy designations and temper designations refer to the Aluminum Standards and Data and the Aluminum Standards and Data published by the Aluminum Association in 2019 and known to those skilled in the art. It means the Aluminum Association notation in Registration Records. Tempering designations are also specified in the European standard EN515.

All references to percentages in any description of alloy compositions or preferred alloy compositions are by weight unless otherwise specified.

As used herein, the terms "up to" and "up to about" expressly include, but are not limited to, the possibility of zero weight percent of the particular alloyed component to which the term refers. For example, 0.08% Zn max may include Zn-free aluminum alloys.

An object of the present invention is to provide a method for manufacturing an aluminum alloy plate of Al--Mg--Si series aluminum alloy or 6XXX series aluminum alloy for forming a vacuum chamber member. Another object of the present invention is to provide a method for manufacturing a vacuum chamber member from an Al--Mg--Si based aluminum alloy plate. A further object of the present invention is to provide a method for manufacturing valves and total assemblies from Al--Mg--Si based aluminum alloy plates.
These and other objects and further advantages are met or exceeded by the present invention, which provides a method for manufacturing aluminum alloy plates for vacuum chamber members, the method comprising, in the following order: ,
(a) 0.80% to 1.05% Mg,
Si 0.70% to 1.0%,
Mn 0.70% to 0.90%,
Fe max 0.20%,
Zn max 0.08%, preferably max 0.05%,
Cu max 0.05%, preferably max 0.03%,
Cr max 0.03%, preferably max 0.02%,
Ti maximum 0.06%, preferably 0.01% to 0.06%,
each <0.03%, total <0.10% unavoidable impurities, balance aluminum,
(% by weight) of Al--Mg--Si based aluminum alloy rolling feedstock;
(b) homogenizing the rolling feedstock at a temperature in the range of 550°C to 595°C;
(c) hot rolling the homogenized rolling feed in one or more rolling steps into a hot rolled plate having a thickness of at least 10 mm;
(d) performing a solution heat treatment (“SHT”) of the hot rolled sheet at a temperature in the range of 540° C. to 590° C.;
(e) rapid cooling or quenching of the SHT plate, preferably by one of injection quenching or immersion quenching in water or other quenching media;
(f) stretching the chilled SHT plate to obtain an elongation set of 1% to 5%;
(g) artificially aging the drawn sheet, preferably to the T6 state (e.g. T651) or T7 state (e.g. T7651);
including the steps of

By carefully controlling the narrow compositional range of Al--Mg--Si alloys in combination with thermo-mechanical processing, the resulting aluminum alloy plates are theoretically suitable for fabricating vacuum chamber components. The alloy is available in a wide range of thicknesses and can be anodized very well with hard anodic coatings. The aluminum plate material has high mechanical properties that provide good shape stability of the vacuum chamber member. Some properties of the anodized material are determined by the microstructure and composition of the plate material. The plate material has a microstructure with uniformly distributed phases in the interior of the plate, resulting in an anodic layer that is less affected, for example, in terms of plate thickness and uniformity on the surface after anodization. The sheet material obtained according to the invention provides, for example, high resistance to corrosive gases when tested in a foam leak test using 5% HCl and a high breakdown voltage (AC , DC).

In one embodiment, the 55 mm thick Al-Mg-Si based alloy plate in the T651 condition has a tensile yield strength (YS) of at least 250 MPa, or even at least 265 MPa in the LT direction according to applicable standard ISO 6892-1 B have

In one embodiment, the 55 mm thick Al-Mg-Si based alloy plate in the T651 condition has a tensile strength (UTS) of at least 300 MPa, or even at least 310 MPa in the LT direction according to applicable standard ISO 6892-1 B. have.

In one embodiment, the 55 mm thick Al-Mg-Si based alloy plate in the T651 condition has an elongation (A _{50 mm} ).

Mg in combination with Si is a major alloying element in aluminum alloys that provides strength through the formation of the Mg ₂ Si phase. Mg should be in the range 0.80% to 1.05%, preferably in the range 0.85% to 1.05%. A preferred upper limit of the Mg content is 1.0%. Too high a Mg content can lead to the formation of coarse Mg ₂ Si phases that adversely affect the quality of subsequently applied anodized coatings. Too low a Mg content adversely affects the tensile properties of the aluminum sheet.

Si should be in the range of 0.70% to 1.0%. In one embodiment the Si content is at least 0.75%, preferably at least 0.80% and most preferably at least 0.84%. In one embodiment, the upper limit for Si content is 0.95%.

In one embodiment, the Mg/Si ratio (wt%) is greater than 0.9, preferably greater than 1.0, and most preferably greater than 1.05. Reducing the amount of free Si in the aluminum alloy is advantageous in increasing the elongation of the aluminum sheet after the relatively high temperature SHT carried out in accordance with the present invention.

Another important alloying element is Mn, which should be in the range of 0.70% to 0.90% to increase the strength and control the grain structure of the aluminum plate, and is suitable for solution heat treatment and quenching. Recrystallization is brought about later. A preferred lower limit is 0.75%. A preferred upper limit is 0.85%.

Fe is an impurity element that should not exceed 0.20%. After anodization, the Fe level is preferably up to 0.12% in order to control grain size and obtain high mechanical strength and good corrosion resistance. However, it preferably contains at least 0.03%, more preferably at least 0.04%. Too low an Fe content can cause undesirable recrystallized grain coarsening, making the aluminum alloy expensive. Too high an Fe content leads to reduced tensile properties, for example due to the formation of the AlFeSi phase, which adversely affects the breakdown voltage after anodization and also adversely affects the corrosive gas resistance. .

Up to about 0.08% Zn, up to about 0.05% Cu, and up to about 0.03% Cr are acceptable impurities but adversely affect the quality of subsequently applied anodized coatings, e.g. , the corrosive gas resistance is lowered. In one embodiment, Zn is up to about 0.05%, preferably up to about 0.03%. In one embodiment Cu is up to about 0.03%, preferably up to about 0.02%. In one embodiment, Cr is up to about 0.02%.

Up to 0.06% Ti is added as an additive for grain refinement of the as-cast microstructure. In one embodiment, Ti is present in the range of about 0.01%-0.06%, preferably in the range of about 0.01%-0.04%.

The balance consists of aluminum and unavoidable impurities. Impurities are included at a maximum of 0.03% each and a maximum of 0.10% total.

In one embodiment, the Al-Mg-Si based aluminum alloy comprises Mg 0.80%-1.05%, Si 0.70%-1.0%, Mn 0.70%-0.90%, Fe max. 0.20% Zn maximum 0.08% Cu maximum 0.05% Cr maximum 0.03% Ti maximum 0.06% each maximum 0.03% total maximum 0.10% unavoidable impurities; The balance is aluminum (and preferred narrower ranges described and claimed herein), (% by weight).

In one embodiment, the Al—Mg—Si based aluminum alloy is
Mg 0.70% to 1.05%,
Si 0.70% to 1.0%,
Mn 0.60% to 1.0%, preferably up to 0.95%,
Fe max 0.20%,
Zn maximum 0.2%,
Cu max 0.10%,
Cr max 0.05%, preferably max 0.04%,
Ti maximum 0.1%, preferably 0.01% to 0.08%,
Ni maximum 0.06%,
each <0.05%, total <0.15% unavoidable impurities, balance aluminum,
(% by weight).

Al-Mg-Si-Mn based aluminum alloys are subjected to conventional casting techniques in the art for cast products, such as direct chill (DC) casting, electromagnetic casting (EMC) casting, electromagnetic stir (EMS) casting. is used to provide an ingot or slab for manufacture into hot rolled sheet stock, preferably having an ingot thickness of about 220 mm or greater, for example in the range of 400 mm, 500 mm, or 600 mm. After casting the rolling feed, the as-cast ingot is typically ground to remove segregation zones near the casting surface of the ingot. Refining additives, such as those containing titanium and boron or titanium and carbon, which are well known in the art, may be used in situ to obtain a fine as-cast grain structure. used.

The objectives of the homogenization heat treatment include at least the following objectives: (i) to dissolve as much of the coarse soluble phase formed during solidification as possible, and (ii) to reduce the concentration gradient to facilitate the dissolution process. Sometimes. The preheating procedure also achieves some of these goals. The homogenization process is carried out in a temperature range of 550°C to 595°C. In one embodiment, the homogenization temperature is at least 555°C, more preferably at least 565°C. The soaking time at the homogenization temperature ranges from about 1 to 20 hours, preferably does not exceed about 15 hours, and more preferably ranges from about 5 to 15 hours. Applicable heating rates are the usual heating rates in the art.

Hot rolling is performed so as to obtain a hot rolled sheet having a thickness of 10 mm or more. In one embodiment, the upper limit is about 230mm, preferably about 200mm, more preferably about 180mm.

The next important processing step is the solution heat treatment ("SHT") of the hot rolled plate. The sheet should be heated to bring all or substantially all of the soluble alloying elements into solution as much as possible. SHT is preferably carried out at a temperature in the temperature range of about 540°C to 590°C. Higher SHT temperatures lead to more favorable mechanical properties, eg higher _Rm . In one embodiment, the lower limit of SHT temperature is 545°C, preferably 550°C. In one embodiment, the upper limit for SHT temperature is about 580°C, more preferably about 575°C. If the SHT temperature is low, the strength of the aluminum plate will be reduced, and some large Mg ₂ Si phases will remain undissolved, so-called “hot spots” may be created, and the corrosion resistance after anodization will be reduced and fractured. Voltage will drop. For example, at plate thicknesses of up to 50 mm, shorter immersion times, for example, in the range of about 10 to 180 minutes, preferably in the range of 10 to 40 minutes, more preferably in the range of 10 to 35 minutes, are considered very effective. ing. Too long a soaking time at a relatively high SHT temperature causes the growth of several phases that adversely affect the ductility of the aluminum sheet. SHT is generally performed in batch or continuous furnaces. After SHT, it is important to cool the sheet material at a high cooling rate to a temperature below 100°C, preferably below 40°C, to prevent or minimize random precipitation of secondary phases. On the other hand, the cooling rate should preferably not be too high to allow sufficient flatness of the plate and low levels of residual stress. A suitable cooling rate can be achieved by using water, eg water immersion or water jet.

The SHT and quenched sheet is further cold worked, preferably by stretching in the range of about 1% to 5% of its original length to relieve residual stresses therein and flatten the sheet. improve degree. It is preferred that the stretch be in the range of about 1.5% to 4%, more preferably about 2% to 3.5%.

After cooling, the drawn sheet is aged, preferably artificially aged, to result in a more preferably T6 condition, more preferably a T651 condition. In one embodiment, artificial aging is performed at a temperature in the range of 150° C. to 190° C., preferably for a period of 5 to 60 hours.

In one embodiment, the drawn sheet is aged to an overaged T7 condition, preferably a T74 or T76 condition, more preferably a T7651 condition.

A further aspect of the present invention relates to a method for manufacturing a vacuum chamber member, the method manufacturing an Al--Mg--Si based alloy plate having a thickness of at least 10 mm as described and claimed herein. including a step for
(h) machining the aged plate, for example in T6, T651, T7, T74, T76, or T7651 condition, into vacuum chamber members of predetermined shape and dimensions;
(i) surface-treating the vacuum chamber member, preferably by anodizing, preferably resulting in an anodic layer or anodic coating layer, preferably at least 20 μm thick, preferably at least 30 μm thick;
(j) optionally hydrating or sealing such anodized material in deionized water at a temperature of at least 80° C., preferably at a temperature of at least 98° C., preferably for a period of at least about 1 hour; matter,
further comprising the steps of In one embodiment, the hydration is performed in two steps, a first step at a temperature of 30°C to 70°C over a period of at least 10 minutes and a second step at a temperature of at least 98°C over a period of at least about 1 hour. carried out in

In one embodiment, the anodization is performed using an electrolyte containing at least sulfuric acid at a temperature of about 15° C. to 30° C. and a current density of about 1.0 A/dm ² to about 2 A/dm ² . The acid concentration in the anodizing bath is generally in the range of about 5-20% by volume. This process takes about 0.5 to 60 minutes, depending on the desired oxide layer thickness. Sulfuric acid anodization generally produces an oxide layer about 8 microns to about 40 microns thick.

In one embodiment, the anodization is performed using an electrolyte containing at least sulfuric acid at a temperature of about 0° C. to 10° C. and a current density of about 3 A/dm ² to about 4.5 A/dm ² . This process generally takes from about 20 minutes to about 120 minutes. Anodization of this hard coating generally produces an oxide layer about 30 micrometers to about 80 micrometers thick or even thicker.

In some embodiments, materials described herein may have a density of phases and particles having a size greater than 10 μm ² of less than 400 phases per mm ² . For example, the material may have a density of phases and particles with a size greater ^than 10 μm 2 in the range of 100-400 phases per mm ² or in the range of 250-350 phases per mm ² . The phases and particles may include those of the AlFeSi type and those of Mg ₂ Si.

The following examples serve to further illustrate the invention, but do not constitute any limitation of the invention. On the other hand, the means may have various embodiments, modifications and equivalents thereof that will be suggested to those skilled in the art after reading this specification without departing from the spirit of the invention. It will be clearly understood to obtain

Phase analysis experiments were performed on aluminum alloy samples for anodization as described herein. A sample with a thickness of 130 mm (referred to herein as "Sample 1"), a sample with a thickness of 40 mm (referred to herein as "Sample 2"), and a sample with a thickness of 14 mm (referred to herein as "Sample 2"). (referred to as "Sample 3" in the literature). Three locations were analyzed on each of the samples, including a near-surface location (“surface”), a quarter-thickness location (“s/4”), and a half-thickness location (“s/2”). . Seven images per position were captured at 1280×1024 pixels ² (0.382 μm/pixel). Seven images of 0.191 mm ² /image were analyzed, examining approximately 1.34 mm ² at each location (totaling 12.05 mm ² ). Therefore, the samples were extensively investigated.

Images were acquired using an optical microscope with 200× magnification. Samples were prepared in the same manner. No etching was performed. For each sample, grinding and polishing, taking special care to avoid any effects on the data due to the method of preparation (e.g. pores or scratches, which can sometimes be misinterpreted by the use of grayscale analysis tools) carried out.

The analyzed phases and particles were mainly those of the AlFeSi type, as well as those of Mg ₂ Si. Detection was performed using ImageJ software and analysis was performed in grayscale. A sample image is shown in FIG. A filter was used to count only particles with an area greater than 10 μm ² . The results are shown in Table 1 below. The density for each location is shown in the column labeled "Density (Phase/mm ² )" and the average density for each sample (calculated by averaging the three locations for each sample) is labeled "Average Density ( The total average density, calculated by averaging 9 measurements (3 samples, 3 locations per sample), is shown in the column labeled "Phase/mm ² )" and is labeled "Total Average Density of All Samples (Phase /mm ² )”. As shown in Table 1, the density ranges from 250 to 320 phase mm ² .

All patents, publications, and abstracts cited above are hereby incorporated by reference in their entirety. Various embodiments of the invention have been described for carrying out the various objectives of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the invention. Numerous variations and modifications thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the invention as defined in the following claims.

Claims (21)

A method for manufacturing an aluminum alloy plate for a vacuum chamber member, valve or total assembly comprising:
(a) 0.80% to 1.05% Mg,
Si 0.70% to 1.0%,
Mn 0.70% to 0.90%,
Fe max 0.20%,
Zn maximum 0.08%,
Cu max 0.05%,
Cr max 0.03%,
Ti maximum 0.06%,
each <0.03%, total <0.10% unavoidable impurities, balance aluminum,
(% by weight) of Al--Mg--Si based aluminum alloy rolling feedstock;
(b) homogenizing the rolling feedstock at a temperature in the range of 550°C to 595°C;
(c) hot rolling said homogenized rolling feed in one or more rolling steps into a hot rolled plate having a thickness of at least 10 mm;
(d) performing a solution heat treatment (“SHT”) of said hot rolled sheet at a temperature in the range of 540° C. to 590° C.;
(e) rapidly cooling the SHT plate;
(f) stretching the cooled SHT plate to obtain an elongation set of 1% to 5%;
(g) artificially aging the drawn sheet;
The above method, comprising the step of The method of claim 1, wherein said hot rolling of said homogenized rolling feedstock is into a plate having a thickness in the range of 10mm to 230mm. A method according to claim 1 or claim 2, wherein the Mg content ranges from 0.85% to 1.05%. A method according to any one of claims 1 to 3, wherein the Si content ranges from 0.70% to 0.95%. 5. The method of any one of claims 1 to 4, wherein the Mg/Si ratio (wt%) is greater than 0.9. A method according to any one of claims 1 to 5, wherein the Mn content ranges from 0.75% to 0.85%. 7. A method according to any one of claims 1 to 6, wherein the Fe content is max 0.12%. A method according to any one of claims 1 to 7, wherein the Ti content is in the range 0.01% to 0.06%. A method according to any one of the preceding claims, wherein said homogenization of said rolling feed is at a temperature in the range of 555°C to 595°C. A method according to any preceding claim, wherein the solution heat treatment of the hot rolled plate is at a temperature in the range of 545°C to 580°C. A method according to any one of claims 1 to 10, wherein said artificial aging is carried out at a temperature in the range of 150°C to 190°C. 12. The method of claim 11, wherein said artificial aging is performed over a period of 5-60 hours. 13. A method according to any preceding claim, wherein the rapid cooling is performed by one of injection quenching or immersion quenching in water or other quenching media. 14. A method according to any preceding claim, wherein said artificial aging is performed to obtain a T6 temper. (h) machining the aging plate into a vacuum chamber member, valve, or total assembly;
(i) surface treating the vacuum chamber member, the valve, or the total assembly;
15. The method of any one of claims 1 to 14, further comprising the step of 16. The method of claim 15, wherein said surface treatment is performed by anodizing. 17. The method of any one of the preceding claims, wherein the aluminum alloy plate has a density of phases and grains with a size greater than 10 [mu ^] m ^<2> of less than 400 phases per mm<2>. A method for manufacturing an aluminum alloy plate for a vacuum chamber member, valve or total assembly comprising:
(a) 0.70% to 1.05% Mg,
Si 0.70% to 1.0%,
Mn 0.60% to 1.0%,
Fe max 0.20%,
Zn maximum 0.2%,
Cu max 0.10%,
Cr max 0.05%,
Ti maximum 0.1%,
Ni maximum 0.06%,
each <0.05%, total <0.15% unavoidable impurities, balance aluminum,
(% by weight) of Al--Mg--Si based aluminum alloy rolling feedstock;
(b) homogenizing the rolling feedstock at a temperature in the range of 550°C to 595°C;
(c) hot rolling said homogenized rolling feed in one or more rolling steps into a hot rolled plate having a thickness of at least 10 mm;
(d) performing a solution heat treatment (“SHT”) of said hot rolled sheet at a temperature in the range of 540° C. to 590° C.;
(e) rapidly cooling the SHT plate;
(f) stretching the cooled SHT plate to obtain an elongation set of 1% to 5%;
(g) artificially aging the drawn sheet;
The above method, comprising the step of 19. The method of claim 18, wherein the rapid cooling is performed by one of injection quenching or immersion quenching in water or other quenching media. A method according to claim 18 or claim 19, wherein said artificial aging is carried out at a temperature in the range of 150°C to 190°C for a period of 5 to 60 hours. 21. A method according to any one of claims 18 to 20, wherein said artificial aging is performed to obtain a T6 temper.

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