CN117083252A - Silica glass member and method for producing same - Google Patents
Silica glass member and method for producing same Download PDFInfo
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- CN117083252A CN117083252A CN202280025606.3A CN202280025606A CN117083252A CN 117083252 A CN117083252 A CN 117083252A CN 202280025606 A CN202280025606 A CN 202280025606A CN 117083252 A CN117083252 A CN 117083252A
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims abstract description 129
- 238000004519 manufacturing process Methods 0.000 title claims description 17
- 238000004891 communication Methods 0.000 claims abstract description 19
- 238000004438 BET method Methods 0.000 claims abstract description 6
- 239000011261 inert gas Substances 0.000 claims description 12
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 9
- 239000004071 soot Substances 0.000 claims description 8
- 239000011575 calcium Substances 0.000 claims description 7
- 239000011651 chromium Substances 0.000 claims description 6
- 239000010949 copper Substances 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 6
- 239000012535 impurity Substances 0.000 claims description 6
- 239000011777 magnesium Substances 0.000 claims description 6
- 239000011572 manganese Substances 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 239000011734 sodium Substances 0.000 claims description 6
- 239000010936 titanium Substances 0.000 claims description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 5
- 229910052700 potassium Inorganic materials 0.000 claims description 4
- 239000004065 semiconductor Substances 0.000 claims description 4
- 150000003377 silicon compounds Chemical class 0.000 claims description 4
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 3
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- 229910052782 aluminium Inorganic materials 0.000 claims description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 3
- 229910052793 cadmium Inorganic materials 0.000 claims description 3
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims description 3
- 229910052791 calcium Inorganic materials 0.000 claims description 3
- 229910052804 chromium Inorganic materials 0.000 claims description 3
- 239000010941 cobalt Substances 0.000 claims description 3
- 229910017052 cobalt Inorganic materials 0.000 claims description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 229910052744 lithium Inorganic materials 0.000 claims description 3
- 229910052749 magnesium Inorganic materials 0.000 claims description 3
- 229910052748 manganese Inorganic materials 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 239000011591 potassium Substances 0.000 claims description 3
- 229910052709 silver Inorganic materials 0.000 claims description 3
- 239000004332 silver Substances 0.000 claims description 3
- 229910052708 sodium Inorganic materials 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- 229910052684 Cerium Inorganic materials 0.000 claims description 2
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 claims description 2
- 230000007062 hydrolysis Effects 0.000 claims description 2
- 238000006460 hydrolysis reaction Methods 0.000 claims description 2
- 238000010191 image analysis Methods 0.000 claims description 2
- 239000011701 zinc Substances 0.000 claims 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims 1
- 229910052742 iron Inorganic materials 0.000 claims 1
- 229910052725 zinc Inorganic materials 0.000 claims 1
- 235000012431 wafers Nutrition 0.000 description 37
- 238000000034 method Methods 0.000 description 21
- 239000007789 gas Substances 0.000 description 9
- 238000005498 polishing Methods 0.000 description 8
- 238000012545 processing Methods 0.000 description 8
- 238000004140 cleaning Methods 0.000 description 6
- 238000005187 foaming Methods 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000000879 optical micrograph Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 238000005520 cutting process Methods 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 238000003754 machining Methods 0.000 description 3
- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical compound C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- 238000000231 atomic layer deposition Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 229910052736 halogen Inorganic materials 0.000 description 2
- 150000002367 halogens Chemical class 0.000 description 2
- 229910052743 krypton Inorganic materials 0.000 description 2
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 230000011218 segmentation Effects 0.000 description 2
- 239000005049 silicon tetrachloride Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- JBQYATWDVHIOAR-UHFFFAOYSA-N tellanylidenegermanium Chemical compound [Te]=[Ge] JBQYATWDVHIOAR-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910002808 Si–O–Si Inorganic materials 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 229910021417 amorphous silicon Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- SLLGVCUQYRMELA-UHFFFAOYSA-N chlorosilicon Chemical compound Cl[Si] SLLGVCUQYRMELA-UHFFFAOYSA-N 0.000 description 1
- 238000012217 deletion Methods 0.000 description 1
- 230000037430 deletion Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229960002050 hydrofluoric acid Drugs 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052754 neon Inorganic materials 0.000 description 1
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 238000009931 pascalization Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- FDNAPBUWERUEDA-UHFFFAOYSA-N silicon tetrachloride Chemical compound Cl[Si](Cl)(Cl)Cl FDNAPBUWERUEDA-UHFFFAOYSA-N 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Glass Melting And Manufacturing (AREA)
Abstract
The present application relates to a silica glass member having a plurality of bubbles, wherein a part or all of the plurality of bubbles are communication bubbles, and S/S0 is 1.5 or more. S: surface area S0 obtained by BET method for a 40mm×8mm×0.5mm sample cut from the silica glass member: geometric surface area determined based on the external dimensions of the sample.
Description
Technical Field
The present application relates to a silica glass member and a method for producing the same.
Background
Conventionally, in the manufacture of semiconductor devices, a batch-type vertical heat treatment apparatus is used to perform film formation processing on a plurality of wafers supported by a multi-stage wafer boat at a time. As film forming processes, ALD (atomic layer deposition method, atomic Layer Depositon) and CVD (chemical vapor deposition ) are generally used.
In this case, the upper and lower stages of the wafer boat may support dummy wafers without supporting product wafers. By supporting the dummy wafer, the gas flowing in the processing container and the uniformity of the temperature between the product wafers can be improved, and the uniformity of film formation on the product wafers can be improved.
In addition, a concave-convex pattern may be formed on the surface of the dummy wafer by machining. By forming the concave-convex pattern on the dummy wafer, the difference between the surface area of the dummy wafer and the surface area of the product wafer on which the concave-convex pattern is formed at a high density is reduced, and the variation in the gas supply amount in the process container is reduced, so that the uniformity of film formation between the product wafers can be further improved (see patent document 1).
Prior art literature
Patent literature
Patent document 1: japanese patent application laid-open No. 2015-173154
Disclosure of Invention
However, the concave-convex pattern of the product wafer is continuously miniaturized year by year, and accordingly, further improvement of the surface area of the dummy wafer is required.
In a dummy wafer having a concave-convex pattern formed thereon, it is generally necessary to narrow the pitch of the concave-convex in order to further increase the surface area. However, if the irregularities having a narrow pitch are formed, the projections are elongated, and therefore, fragments may be easily generated. The chips become particles, which may cause a reduction in yield.
The present application has been made in view of the above problems, and an object of the present application is to provide a technique for obtaining a dummy wafer in which the surface area is increased and the occurrence of particles is suppressed.
The present application relates to the following [1] to [10].
[1] A silica glass member having a plurality of bubbles, wherein some or all of the plurality of bubbles are communication bubbles, and S/S0 is 1.5 or more.
S: surface area obtained by BET method on a 40mm X8 mm X0.5 mm sample cut from the silica glass member
S0: geometric surface area determined based on the external dimensions of the above sample
[2] The silica glass member according to [1], wherein S/S0 is 4 or more.
[3] The silica glass member according to [1], wherein S/S0 is 5 or more.
[4] The silica glass member according to any one of [1] to [3], wherein an average bubble diameter of the bubbles obtained by image analysis of an X-ray CT image is 30 μm to 150 μm.
[5]According to [1]]～[4]The silica glass member according to any one of, wherein the bulk density is 0.3g/cm 3 ～2g/cm 3 。
[6] The silica glass member according to any one of [1] to [5], wherein a ratio of the number of the communicating bubbles to the number of the plurality of bubbles is 30% to 100%.
[7] The silica glass member according to any one of [1] to [5], wherein a ratio of the number of the communicating bubbles to the number of the plurality of bubbles is 70% to 100%.
[8] The silica glass member according to any one of [1] to [7], wherein the content of each metal impurity of lithium (Li), aluminum (Al), chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), titanium (Ti), cobalt (Co), zinc (Zn), silver (Ag), cadmium (Cd), lead (Pb), sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), cerium (Ce) and iron (Fe) is 0.5 mass ppm or less, respectively.
[9] The silica glass member according to any one of [1] to [8], wherein the silica glass member is used as a dummy wafer for a vertical heat treatment apparatus in semiconductor manufacturing.
[10] A method for producing a silica glass member having a plurality of bubbles, a part or all of the plurality of bubbles being communication bubbles, wherein when a surface area obtained by a BET method on a 40mm×8mm×0.5mm sample cut out from the silica glass member is S and a geometric surface area obtained based on an external dimension of the sample is S0, S/S0 is 1.5 or more, the method comprising the steps of:
silica particles produced by flame hydrolysis of a silicon compound are deposited to obtain a soot body,
the soot body is densified in an inert gas atmosphere to obtain a silica glass compact,
a silica glass porous body obtained by making the silica glass compact porous under a condition of at least a low pressure or a high temperature as compared with the condition of obtaining the silica glass compact, and
the silica glass porous body is processed to obtain a silica glass member having an arbitrary shape.
According to the present application, a dummy wafer in which particle generation is suppressed while the surface area is increased can be obtained.
Drawings
Fig. 1 is a view showing a silica glass member according to an embodiment, fig. 1 (a) is a perspective view of the member, and fig. 1 (B) is a cross-sectional view of the member in the direction of the arrow X-X' of (a).
Fig. 2 is a diagram showing a structural change when cleaning only the upper surface of the silica glass member according to one embodiment.
Fig. 3 is a flowchart showing a method for manufacturing a silica glass member according to an embodiment.
Fig. 4 is an optical microscope image obtained by optically polishing the cut surface of the silica glass member of example 1.
Fig. 5 is an optical microscope image obtained by optically polishing the cut surface of the silica glass member of example 3.
Fig. 6A is a diagram for explaining a method of calculating the average bubble diameter, and is an X-ray CT image obtained by removing noise from a sample obtained by optically polishing the surface of an evaluation target.
Fig. 6B is a diagram for explaining a method of calculating the average bubble diameter, and is an image obtained by binarizing the image of fig. 6A.
Fig. 6C is a diagram for explaining a method of calculating the average bubble diameter, and is an image obtained by performing the watered segmentation process in fig. 6B.
Detailed Description
Hereinafter, embodiments of the present application (hereinafter, simply referred to as "present embodiments") will be described in detail with reference to the drawings. In the drawings, unless otherwise specified, the positional relationship between the upper, lower, left, right, etc. is based on the positional relationship shown in the drawings. The dimensional ratios in the drawings are not limited to the ratios shown. In the specification, "to" indicating a numerical range means that the numerical values described before and after the numerical range are included as a lower limit value and an upper limit value. The lower limit and the upper limit include rounded ranges.
First, the structure of a silica glass member 1 according to the present embodiment will be described with reference to fig. 1.
Fig. 1 (a) is a perspective view of a silica glass member 1, and fig. 1 (B) is a cross-sectional view of (a) in the direction of the arrow X-X'.
Although the silica glass member 1 shown in fig. 1 (a) is a cube, the shape is not particularly limited. When used as a dummy wafer, the dummy wafer is preferably substantially the same shape as the product wafer.
As shown in fig. 1 (B), the silica glass member 1 has a silica glass portion 10 and a plurality of bubbles 12. The bubbles 12 include non-communicating bubbles 14 and communicating bubbles 16.
The silica glass part 10 is made of amorphous silicon oxide (SiO 2 ) Is a main component and is transparent. In addition, the density is about 2.2g/cm 3 . The silica glass part 10 is made of SiO 2 In addition, different elements may be contained for the purpose of controlling the characteristics of the silica glass portion 10.
The non-communicating bubbles 14 are substantially uniformly dispersed in the silica glass member 1, and contain a gas therein. The shape of the non-communicating bubble 14 is not particularly limited, and is a substantially spherical shape or a substantially oblate spherical shape.
The communication bubbles 16 are formed by communicating adjacent non-communication bubbles 14 with each other. In fig. 1 (B), although two-dimensional communication is described, three-dimensional communication is naturally also possible. Some or all of the bubbles 12 contained in the silica glass member 1 form communication bubbles 16.
In the cross-sectional view of fig. 1 (B), there are bubbles that do not appear to communicate with each other, but actually communicate with each other in three dimensions, and in this specification, such bubbles are regarded as non-communicating bubbles 14 for convenience.
As shown in fig. 1 (a), a plurality of pits 18 are formed in the surface of the silica glass member 1. The pits 18 are formed by non-communicating bubbles 14 or communicating bubbles 16 exposed to the surface. The appearance of the pit 18 has a substantially circular or substantially elliptical shape, or a shape in which they are connected. The silica glass member 1 having the pits 18 increases the surface area and is therefore suitable as a dummy wafer.
Next, characteristics of the silica glass member 1 according to the present embodiment will be described.
The value (S/S0) obtained by dividing the surface area S of the silica glass member 1 by the geometric surface area S0 calculated based on the outer dimension of the silica glass member 1 is 1.5 or more, preferably 3 or more, more preferably 4 or more, still more preferably 5 or more, still more preferably 6 or more, and most preferably 8 or more. If S/S0 is 1.5 or more, it can be said that the surface area of the silica glass member 1 is sufficiently large, and thus the uniformity of film formation on the product wafer is improved. In addition, as S/S0 increases, the dummy wafer is sometimes more suitable as a dummy wafer for use with product wafers that have been miniaturized in recent years. The geometric surface area S0 is a hypothetical surface area obtained assuming that the surface of the silica glass member 1 is a flat surface without the pits 18.
The average bubble diameter of the bubbles 12 is preferably 30 μm in the lower limit, more preferably 40 μm, still more preferably 50 μm, and preferably 150 μm in the upper limit, more preferably 120 μm. If the average bubble diameter is within this range, the effect of increasing the surface area can be sufficiently obtained. The average bubble diameter is an average value of the bubble diameters calculated assuming that the shape of the bubbles is a perfect circle. At this time, the communication bubble 16 is divided into a plurality of regions by a method described later, and the bubble diameter is determined by considering the divided regions as 1 bubble.
The lower limit of the bulk density of the silica glass member 1 is preferably 0.3g/cm 3 More preferably 0.5g/cm 3 The upper limit is preferably 2g/cm 3 More preferably 1.6g/cm 3 . If the bulk density is 0.3g/cm 3 As described above, the strength of the silica glass member 1 is sufficiently obtained. In addition, if the bulk density is 2g/cm 3 Hereinafter, the silica glass member 1 contains bubbles 12 sufficiently to increase the surface area, and thus can be suitably used as a dummy wafer.
The ratio of the number of the communication bubbles 16 to the number of the plurality of bubbles 12 (the sum of the number of the non-communication bubbles 14 and the number of the communication bubbles 16) (hereinafter referred to as a communication bubble ratio) is preferably 30% or more, more preferably 50% or more, and still more preferably 70% or more. If the communication bubble ratio is 30% or more, the probability of forming the pit 18 as the communication bubble 16 increases, and as a result, the surface area of the dummy wafer increases sufficiently.
The content of each metal impurity of lithium (Li), sodium (Na), magnesium (Mg), aluminum (Al), potassium (K), calcium (Ca), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), titanium (Ti), cobalt (Co), zinc (Zn), silver (Ag), cadmium (Cd), and lead (Pb) in the silica glass portion 10 is preferably 0.5 mass ppm or less, more preferably 0.1 mass ppm or less, respectively. If the content of each metal impurity is 0.5 mass ppm or less, it can be suitably used as a component used in a semiconductor manufacturing apparatus. In the specification, ppm means parts per million and ppb means parts per billion.
The silica glass member 1 having the above-described structure has fewer sites where debris can be generated compared to a dummy wafer having a concave-convex pattern formed thereon, and thus is less likely to generate particles.
In addition, the silica glass member 1 is also advantageous from the viewpoint of cleaning resistance.
Generally, the dummy wafer after use is cleaned by dry etching using a fluorine-based gas or the like, or wet etching using a fluoric acid or the like. In this case, the dummy wafer having the concave-convex pattern formed thereon may have concave-convex corners cut off and easily become substantially flat depending on the concave-convex shape thereof, resulting in a reduction in surface area.
On the other hand, the silica glass member 1 is suppressed in reduction in surface area due to cleaning. The change in the surface area of the silica glass member 1 during cleaning will be described with reference to fig. 2. In fig. 2, it is assumed that only the upper surface of the silica glass member 1 having 3 pits (18 a,18b,18 c) is cleaned. At this time, the upper surface of the silica glass member 1 and the inner wall surfaces of the pits are etched by the cleaning, and as a result, the pits 18b,18c disappear, but the surface area of the inner wall of the pit 18a increases, and new pits 18d, 18e, 18f are formed. In this way, the silica glass member 1 has bubbles 12 inside, and thus the reduction in surface area due to cleaning is suppressed.
Next, a method for manufacturing the silica glass member 1 according to the present embodiment will be described with reference to fig. 3.
In the present embodiment, although the VAD (Vapor axial deposition) method is used as the method for synthesizing silica glass, there is no relation to the production method by appropriately changing the production method as long as the effect of the application is achieved.
As shown in fig. 3, the method for producing the silica glass member 1 includes steps S21 to S25.
In step S21, a synthetic raw material of silica glass is selected. The synthetic raw material of silica glass is not particularly limited as long as it is a gasifiable silicon-containing raw material, and typical examples thereof include silicon chloride (for example, siCl 4 、SiHCl 3 、SiH 2 Cl 2 、SiCH 3 Cl 3 ) Silicofluoride (e.g. SiF) 4 、SiHF 3 、SiH 2 F 2 ) Such as halogen-containing silicon compounds, OR RnSi (OR) 4－n (R: alkyl group having 1 to 4 carbon atoms, n: integer of 0 to 3), and (CH) 3 ) 3 Si－O－Si(CH 3 ) 3 And silicon compounds containing no halogen.
Next, in step S22, the synthetic raw material is flame-hydrolyzed at a temperature of 1000 to 1500 ℃ to generate silica particles, which are blown and deposited on the rotating substrate, thereby obtaining a soot body. In the soot body, the silica particles are partially sintered with each other.
Although not shown, the ash material may be dehydrated by heat treatment in a vacuum atmosphere after step S22 to reduce the OH group concentration for the purpose of controlling the electric characteristics. In this case, the temperature at the time of heat treatment is preferably 1000 to 1300℃and the treatment time is preferably 1 to 240 hours.
Next, in step S23, the soot body is subjected to a high-temperature and high-pressure treatment in an inert gas atmosphere, whereby the silica particles in the soot body are sintered and densified to obtain a silica glass compact. The silica glass compact is transparent silica glass containing substantially no bubbles or opaque silica glass containing fine bubbles. In this case, the temperature at the time of the high-temperature high-pressure treatment is preferably 1200 to 1700 ℃, the pressure is preferably 0.01 to 200MPa, and the treatment time is preferably 10 to 100 hours.
In step S23, the inert gas is dissolved in silica glass. The inert gas is typically helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), nitrogen (N) 2 ) Or a mixed gas containing at least 2 or more of them, which will be described later in detail, ar is preferable. It is generally known that the solubility of an inert gas in silica glass tends to decrease as the partial pressure of the inert gas in the atmosphere is lower or the temperature of the silica glass is higher.
Next, in step S24, the silica glass compact is subjected to high-temperature low-pressure treatment to foam the inert gas dissolved in the silica glass, and the bubbles contained in the silica glass compact are thermally expanded to be porous, thereby obtaining a silica glass porous body having bubbles 12. In this case, the temperature at the time of the high-temperature low-pressure treatment is preferably 1300 to 1800℃and the pressure is preferably 0Pa to 0.1MPa, and the treatment time is preferably 1 minute to 20 hours. If the treatment time is 20 hours or less, there is no concern that the bubbles 12 will be closed by overheating.
Here, the mechanism of foaming will be described. It was also said that the solubility of the inert gas in the silica glass tends to decrease as the partial pressure of the inert gas in the atmosphere is lower or the temperature of the silica glass is higher. Therefore, in step S24, the dissolved amount of the inert gas may reach a supersaturation state by performing the treatment at a lower pressure or a higher temperature than in step S23, and at this time, foaming occurs in the silica glass.
In view of the above mechanism, the foaming can occur even when the temperature at the time of the high-temperature low-pressure treatment of step S24 is lower than the temperature at the time of the high-temperature high-pressure treatment of step S23, but the foaming is promoted more easily when the temperature is higher than the temperature at the time of the high-temperature high-pressure treatment of step S23.
Among the options for the inert gas, ar is preferable from the viewpoints of being relatively inexpensive, having a large temperature dependence of solubility in silica glass, and being easy to control the porosity.
The number, bubble diameter, bulk density, and the like of the bubbles 12 contained in the silica glass member 1 can be controlled by appropriately adjusting the temperature, pressure, and processing time in the high-temperature high-pressure processing of step S23 and the high-temperature low-pressure processing of step S24, and changing the foaming amount and the expansion degree of the bubbles.
Finally, in step 25, the silica glass porous body is processed into an arbitrary shape by a method such as cutting, slicing, grinding, polishing, or the like, to obtain the silica glass member 1. When the silica glass member 1 is used as a dummy wafer, it is preferably substantially the same shape as that of a product wafer.
By the above manufacturing method, the silica glass member 1 suitable as a dummy wafer can be obtained without performing complicated and expensive machining for forming the concave-convex pattern.
The use of the silica glass member 1 is not limited to the dummy wafer, and may be used for various purposes insofar as the characteristics of the silica glass member 1 described in the present specification are favorably used.
Examples
Next, experimental data will be described with reference to table 1, fig. 4 to 5, and fig. 6A to 6C.
Examples 1 to 5
Silicon tetrachloride (SiCl) 4 ) As a synthetic raw material of silica glass, it is flame-hydrolyzed to generate silica particles, which are blown and deposited onto a rotating substrate, thereby obtaining a soot body. Next, the ash material was placed in a heating furnace, filled with Ar gas, subjected to high-temperature high-pressure treatment at a predetermined temperature, pressure and treatment time, densified, and then returned to atmospheric pressure and cooled. The silica glass compact obtained at this time is an opaque silica glass containing fine bubbles. Then, the silica glass compact is subjected to high-temperature low-pressure treatment at a predetermined temperature and a predetermined treatment time to be porous, and then the porous silica glass body is recovered to the atmospheric pressure and cooled. Finally, the silica glass porous body is taken out of the furnace, and is formed into a desired shape by cutting, slicing, grinding, and polishing. The silica glass member 1 having the parameters shown in examples 1 to 5 of table 1 was obtained by arbitrarily combining the temperature, pressure, and treatment time in the high-temperature high-pressure treatment and the high-temperature low-pressure treatment.
Examples 1 to 5 are examples.
Fig. 4 shows an optical microscope image obtained by optically polishing the surface of the silica glass member 1 of example 1. As can be seen from fig. 4: the silica glass member 1 of example 1 had substantially uniformly dispersed bubbles 12, some of which were present as communicating bubbles 16, and S/S0 was 1.9.
Further, the silica glass member 1 of example 1 was measured for the content of metal impurities, and as a result, li, mg, K, cr, mn, fe, ni, cu, ti, co, zn, ag, cd, ce and Pb were less than 3ppb, na was 80ppb, al was 30ppb, and Ca was 10ppb. The content of the metal impurities was obtained by cutting the silica gas member 1 obtained as described above into a suitable size and then using the ICP-MS (Inductively Coupled Plasma-Mass Spectrometer) method.
Fig. 5 shows an optical microscope image obtained by optically polishing the surface of the silica glass member 1 of example 4. As can be seen from fig. 5: the silica glass member 1 of example 4 had substantially uniformly dispersed bubbles 12, some of which were present as connected bubbles 16, and the average bubble diameter was larger and the connected bubble rate was higher than in the case of example 1, so that S/S0 was a high value of 6.9.
In summary, the silica glass member 1 of examples 1 to 5 has a large surface area by containing the bubbles 12 even without machining, and suppresses the generation of particles by this structure, and thus can be suitably used as a dummy wafer.
The parameters shown in table 1 were obtained by the following methods.
(S/S0)
Surface area S is determined by the method based on JIS-Z8830: 2013 by BET method. Specifically, 5 pieces of a plate-like sample were prepared, each of which was cut out to 40mm×8mm×0.5mm, placed in a glass dish, and deaerated under reduced pressure at 200 ℃ for about 5 hours as a pretreatment, and then krypton (Kr) gas was adsorbed and measured by a specific surface area measuring device (belorp-max, manufactured by japan bayer corporation), and the surface area S was obtained by dividing the obtained value by 5 (the number of pieces of the sample). The geometric surface area S0 based on the external dimension of the sample is divided to obtain S/S0.
(average bubble diameter)
The average bubble diameter was obtained in the following procedure (I) to (IV).
(I) First, an X-ray CT image is obtained by an X-ray CT apparatus (TXS-CT 300 manufactured by TESCO) of a sample obtained by optically polishing the surface of an evaluation target, and noise is removed from the image by image processing software (for example, imageJ), thereby obtaining an image as shown in fig. 6A.
(II) then, binarization processing is performed using image processing software (for example, imageJ) to obtain an image as shown in FIG. 6B. At this time, the threshold value of the luminance value of the binarization processing is closest to the evaluation target object as the ratio of the area of the white region (corresponding to the air bubble 12) to the area of the entire image of fig. 6BIs determined by means of the bubble rate of the gas. Here, since the silica glass substantially free of bubbles has a density of 2.2g/cm 3 Therefore, the bubble ratio is obtained from the following formula (1) using the bulk density ρ described below. In fig. 6B, the white region cut at the image end was ignored in the calculation of the average bubble diameter.
(bubble ratio) = (2.2- ρ)/2.2 … (1)
(III) next, the processing of dividing the connected bubbles is performed by the Watershed dividing processing, whereby an image as shown in fig. 6C is obtained. Here, the Watershed segmentation process is performed in the following order:
making an Euclidean Distance Map (EDM) for the image of FIG. 6B, detecting extreme erosion points (UEPs) of the EDM, either as vertices or as vertices;
expanding each UEP to reach the end of each bubble or to the edge of the UEP region expanded by the communicating bubbles;
the communicating bubbles are segmented based on the respective expanded UEP regions.
(IV) next, the area a of the divided region (e.g., 6 a) and the area a of the non-divided region (e.g., 6 b) in fig. 6C were obtained, respectively, and the bubble diameter D was calculated from the following formula (2). For each 1 sample, 200 or more bubble diameters D were obtained, and the average value was used as the average bubble diameter.
(bulk Density)
The object to be evaluated was cut into a rectangular parallelepiped shape of 40mm×8mm×0.5mm, and the mass was measured by an electronic balance. Bulk density was determined by dividing this by the apparent volume of the sample.
(communicating bubble ratio)
In fig. 6C, the white area that is not divided is regarded as non-connected bubbles, the white area that is divided is regarded as connected bubbles, and the number of connected bubbles is divided by the total number of bubbles (sum of the number of non-connected bubbles and the number of connected bubbles) to determine the connected bubble ratio. In fig. 6C, the white region cut at the image end is ignored in the calculation of the connected bubble ratio.
TABLE 1
The silica glass porous body and the method for producing the same according to the present application have been described above, but the present application is not limited to the above-described embodiments and the like. Various changes, modifications, substitutions, additions, deletions and combinations may be made within the scope described in the claims. They are of course also within the scope of the technique of the present application.
The present application is based on Japanese patent applications (Japanese patent application No. 2021-065433) filed on 7 th month 4 of 2021, japanese patent application No. 2021-135895 filed on 8 th month 23 of 2021, and the contents thereof are incorporated herein by reference.
Symbol description
1. Silica glass component
10. Silica glass part
12. Air bubble
14. Non-communicating bubbles
16. Communicating bubbles
18. Pit
Claims (10)
1. A silica glass member having a plurality of bubbles, wherein a part or all of the plurality of bubbles are communication bubbles, S/S0 is 1.5 or more,
s: a surface area obtained by BET method was used for a 40mm X8 mm X0.5 mm sample cut from the silica glass member,
s0: geometric surface area determined based on the external dimensions of the sample.
2. The silica glass member according to claim 1, wherein the S/S0 is 4 or more.
3. The silica glass member according to claim 1, wherein the S/S0 is 5 or more.
4. The silica glass member according to any one of claims 1 to 3, wherein the average bubble diameter of the bubbles obtained by image analysis of an X-ray CT image is 30 μm to 150 μm.
5. Silica glass component according to any one of claims 1 to 4, wherein the bulk density is 0.3g/cm 3 ～2g/cm 3 。
6. The silica glass member according to any one of claims 1 to 5, wherein a ratio of the number of the communication bubbles to the number of the plurality of bubbles is 30% to 100%.
7. The silica glass member according to any one of claims 1 to 5, wherein a ratio of the number of the communication bubbles to the number of the plurality of bubbles is 70% to 100%.
8. The silica glass member according to any one of claims 1 to 7, wherein the content of each metal impurity of lithium Li, aluminum Al, chromium Cr, manganese Mn, nickel Ni, copper Cu, titanium Ti, cobalt Co, zinc Zn, silver Ag, cadmium Cd, lead Pb, sodium Na, magnesium Mg, potassium K, calcium Ca, cerium Ce, and iron Fe is 0.5 mass ppm or less, respectively.
9. The silica glass member according to any one of claims 1 to 8, which is used as a dummy wafer for a vertical heat treatment apparatus in semiconductor manufacturing.
10. A method for producing a silica glass member, wherein the silica glass member has a plurality of bubbles, a part or all of the plurality of bubbles are communication bubbles, the surface area obtained by the BET method of a sample of 40mm x 8mm x 0.5mm cut out from the silica glass member is S, the geometric surface area obtained based on the external dimensions of the sample is S0, S/S0 is 1.5 or more,
the manufacturing method comprises the following steps:
silica particles produced by flame hydrolysis of a silicon compound are deposited to obtain a soot body,
densifying the gray material body in an inert gas atmosphere to obtain a silica glass densified body,
a silica glass porous body obtained by making the silica glass compact porous under conditions of at least low pressure or high temperature as compared with the conditions under which the silica glass compact is obtained, and
the silica glass porous body is processed to obtain a silica glass member of an arbitrary shape.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2021-065433 | 2021-04-07 | ||
| JP2021-135895 | 2021-08-23 | ||
| JP2021135895 | 2021-08-23 | ||
| PCT/JP2022/016901 WO2022215663A1 (en) | 2021-04-07 | 2022-03-31 | Silica glass member and method for producing same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117083252A true CN117083252A (en) | 2023-11-17 |
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ID=88708477
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202280025606.3A Pending CN117083252A (en) | 2021-04-07 | 2022-03-31 | Silica glass member and method for producing same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117083252A (en) |
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2022
- 2022-03-31 CN CN202280025606.3A patent/CN117083252A/en active Pending
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