SEMICONDUCTOR HEAT TREATMENT MEMBER

Abstract

A semiconductor heat treatment member includes a plurality of quartz glass members fused to one another, a plurality of devitrified portions are formed in a fused portion at which the quartz glass members are fused, a maximum cross-sectional area of one devitrified portion among the plurality of devitrified portions is 1.76 mm.sup.2 or less, and an area occupancy ratio of a total area of the plurality of devitrified portions to an area of a cross section of the fused portion is 10% or less.

Claims

1. A semiconductor heat treatment member comprising a plurality of quartz glass members fused to one another, wherein a plurality of devitrified portions are formed in a fused portion at which the quartz glass members are fused, a maximum cross-sectional area of one devitrified portion among the plurality of devitrified portions is 1.76 mm.sup.2 or less, and an area occupancy ratio of a total area of the plurality of devitrified portions to an area of a cross section of the fused portion is 10% or less.

2. The semiconductor heat treatment member according to claim 1, wherein a volume occupancy ratio per unit volume of the devitrified portion in a main body of the semiconductor heat treatment member other than the fused portion is 0.015% or less.

3. The semiconductor heat treatment member according to claim 1, wherein each of the plurality of quartz glass members has an Al content of 5 ppm by weight or more and 25 ppm by weight or less.

4. The semiconductor heat treatment member according to claim 2, wherein each of the plurality of quartz glass members has an Al content of 5 ppm by weight or more and 25 ppm by weight or less.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0020] FIG. 1 is a perspective view of a semiconductor heat treatment member according to the present invention.

[0021] FIG. 2A is an enlarged front view of a part of the semiconductor heat treatment member in FIG. 1, and FIG. 2B is a plan view of FIG. 2A.

[0022] FIG. 3 is a conceptual diagram illustrating a method of measuring a breaking strength by a three-point bending test.

[0023] FIG. 4 is a conceptual diagram illustrating a method of evaluating thermal deformation by calculating a deformation amount from lengths before and after fusion of a quartz glass plate.

[0024] FIG. 5 is a conceptual diagram illustrating a plurality of devitrified portions formed in a fused portion.

[0025] FIG. 6 is a conceptual diagram illustrating a plurality of devitrified portions formed in a main body other than the fused portion.

DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, an embodiment of a semiconductor heat treatment member according to the present invention will be described with reference to FIGS. 1, 2A, and 2B.

[0027] FIG. 1 is a perspective view illustrating a part of a chamber as the semiconductor heat treatment member according to the present invention, FIG. 2A is an enlarged front view illustrating a part (portion surrounded by broken line in FIG. 1) of the semiconductor heat treatment member in FIG. 1, and FIG. 2B is a plan view of FIG. 2A and an enlarged plan view illustrating a part of the semiconductor heat treatment member in FIG. 1.

[0028] The drawings are schematic or conceptual, and the relationship between the thickness and the width of each portion, the size ratio between portions, etc. are not accurately illustrated.

[0029] As illustrated in FIG. 1, a chamber 1 (semiconductor heat treatment member) is implemented by assembling a plurality of (five in the drawing) rectangular quartz glass plates 2 (quartz glass members) having a predetermined thickness.

[0030] In the illustrated example, two side plates 2a and 2b, one top plate 2c, one bottom plate 2d, and one back plate 2e, which are made of quartz glass, are connected. That is, in this example, the chamber 1 is formed in a box shape opened forward.

[0031] The quartz glass plates 2 are fusion-bonded at end portions (end surfaces or edges) thereof.

[0032] Specifically, the quartz glass plates 2 are heated and fused while applying a predetermined pressure at the end portions of the quartz glass plates 2. Accordingly, devitrification occurs at a fused portion F illustrated in FIGS. 2A and 2B and a main body main body other than the fused portion F.

[0033] Here, the fused portion F refers to an interface between two quartz glass plates 2 that are fusion-bonded. In addition, the main body other than the fused portion F means the inside of the quartz glass plate 2 except for an outer surface, which is a portion other than the fused portion F (interface) in the quartz glass plate 2.

[0034] As illustrated in FIG. 5, devitrification occurs in the fused portion F. The devitrification occurred in the fused portion F has a linear or planar shape, and a plurality of linear or planar devitrifications are present in the fused portion F.

[0035] Here, the devitrifications are referred to as devitrified portions X, and the devitrified portions X are illustrated in FIG. 5. FIG. 5 is a diagram for facilitating understanding, is a schematic or conceptual diagram, and does not accurately illustrate a size of the devitrified portion X.

[0036] In the fused portion F, the devitrified portion X is planar or linear, but a maximum cross-sectional area of one devitrified portion X is 1.76 mm.sup.2 or less, and a total area of all the devitrified portions X (total area occupancy ratio) is 10% or less with respect to a cross-sectional area of the fused portion F.

[0037] When the maximum cross-sectional area of one devitrified portion X in the fused portion F exceeds 1.76 mm.sup.2, the strength decreases, which is not preferable.

[0038] In addition, when the total area of all the devitrified portions X (total area occupancy ratio) exceeds 10% with respect to the cross-sectional area of the fused portion F, the strength decreases, which is not preferable.

[0039] Here, the maximum cross-sectional area of the devitrified portion X refers to a cross section obtained by cutting the devitrified portion at any angle, and satisfies the above range in a cross section at any angle. In addition, the cross-sectional area of the fused portion F refers to a cross section of the fused portion F cut along a fusion interface.

[0040] As illustrated in FIG. 6, a plurality of spherical devitrifications occur in the main body other than the fused portion F. The devitrifications occur at the time of forming the fused portion F.

[0041] Here, the devitrifications are referred to as devitrified portions Y. FIG. 6 illustrates the devitrified portions Y. FIG. 6 is a diagram for facilitating understanding, is a schematic or conceptual diagram, and does not accurately illustrate the size of the devitrified portion Y.

[0042] In the semiconductor heat treatment member according to the embodiment of the present invention, five or less spherical devitrified portions Y having an average diameter of 2 mm or more, ten or less devitrified portions Y having an average diameter of 1 mm or more and less than 2 mm, and 15,000 or less devitrified portions Y having an average diameter of less than 1 mm are formed in the main body other than the fused portion F.

[0043] The devitrified portions Y existing in the main body other than the fused portion F have the above distribution, so that it is possible to suppress a decrease in strength.

[0044] In the main body other than the fused portion F, the devitrified portion Y is spherical, and a volume occupancy ratio of a total volume of the devitrified portions Y per unit volume is preferably 0.015% or less.

[0045] When the volume occupancy ratio of the total volume of the devitrified portions Y in the main body other than the fused portion F is 0.015% or less, a decrease in strength can be suppressed. Furthermore, deformation due to heat can be suppressed.

[0046] The semiconductor heat treatment member preferably has an Al content of 5 ppm by weight or more and 25 ppm by weight or less. When the Al content falls within the above range, a decrease in strength can be suppressed.

[0047] More preferably, a Ca content is 2.0 ppm by weight or less, an Mg content is 0.3 ppm by weight or less, and a Na content is 0.5 ppm by weight or less. When the Ca content and the like are within the above ranges, a decrease in strength can be suppressed.

[0048] Next, a method of manufacturing the chamber 1 as a semiconductor heat treatment member will be described.

[0049] First, five quartz glass plates 2 (side plates 2a and 2b, top plate 2c, bottom plate 2d, and back plate 2e) constituting the chamber 1 which is a semiconductor heat treatment member are prepared.

[0050] The quartz glass plates 2 have an Al content of 5 ppm by weight or more and 25 ppm by weight or less, a Ca content of 2.0 ppm by weight or less, an Mg content of 0.3 ppm by weight or less, and a Na content of 0.5 ppm by weight or less. As long as the Al content is within the above range, a commercially available quartz glass plate may be used.

[0051] Next, the quartz glass plates 2 are heated at a temperature of 1,000 C. or higher and 1,700 C. or lower, and end portions thereof are fused by being pressed in opposite directions at 0.1 kg/cm.sup.2 or more and 10 kg/cm.sup.2 or less.

[0052] That is, in the case of the chamber 1 illustrated in FIG. 1, for example, left and right edge portions of the bottom plate 2d are welded to lower end surfaces of the side plates 2a and 2b, respectively, and upper end surfaces of the side plates 2a and 2b are welded to left and right edge portions of the top plate 2c, respectively. Then, rear end surfaces of the side plates 2a and 2b, the bottom plate 2d, and the top plate 2c are welded to four edge portions of the back plate 2e.

[0053] In this manner, end portions of all the quartz glass plates 2 are connected, followed by cooling, thereby obtaining the chamber 1 (semiconductor heat treatment member) having the shape illustrated in FIG. 1.

[0054] As described above, according to the present invention, when the quartz glass plates 2 are connected, the quartz glass plates 2 are heated at a temperature of 1,000 C. or higher and 1,700 C. or lower and are pressed to be fused. When the temperature is lower than 1,000 C., the plates are not sufficiently fused and the strength decreases due to the low temperature. When the temperature exceeds 1,700 C., the shape of the quartz glass plates 2 cannot be maintained due to the high temperature.

[0055] Regarding pressing during fusion, it is desirable that the end portions are pressed in opposite directions at 0.1 kg/cm.sup.2 or more and 10 kg/cm.sup.2 or less.

[0056] The quartz glass plate 2 can be fused without deformation by being pressed at 0.1 kg/cm.sup.2 or more and 10 kg/cm.sup.2 or less. In addition, the end portions of the quartz glass plates 2 can be uniformly fused.

[0057] In the fused portion F where the quartz glass plates 2 are fused, the devitrified portion X is planar or linear, but a maximum cross-sectional area of one devitrified portion X is 1.76 mm.sup.2 or less, and a total area of all the devitrified portions X (area occupancy ratio) is 10% or less with respect to a cross-sectional area of the fused portion F.

[0058] The maximum cross-sectional area of one devitrified portion X and the total area (area occupancy ratio) of the devitrified portions X are controlled by a degree of pressurization, a degree of heating temperature of the quartz glass plate 2, or a degree of Al content of the quartz glass member.

[0059] In the above embodiment, the chamber 1 in which a plurality of quartz glass plates are fused as the semiconductor heat treatment member according to the present invention is illustrated, but the present invention is not limited to this embodiment, and can be widely applied to a semiconductor heat treatment member formed by fusing quartz glass members.

EXAMPLES

[0060] A semiconductor heat treatment member and a manufacturing method thereof according to the present invention will be further described based on examples.

Experiment

[0061] In an experiment, a maximum cross-sectional area (mm.sup.2) of one devitrified portion among devitrified portions, a total area (area occupancy ratio %) of all the devitrified portions with respect to a cross-sectional area of the fused portion F, and a volume occupancy ratio % of the devitrified portion other than the fused portion F were verified in order to ensure a breaking strength required for the semiconductor heat treatment member and sufficiently suppress thermal deformation in the fused portion.

Example 1

[0062] In Example 1, two quartz glass plates (Al: 10 ppm by weight, Ca: 1.0 ppm by weight, Mg: 0.1 ppm by weight, and Na: 0.1 ppm by weight) were prepared. The quartz glass plate had a length of 100 mm, a width of 100 mm, and a thickness of 30 mm, and two quartz glass plates having the same dimensions were prepared. No devitrification was observed in the two quartz glass plates. The content of each element in the quartz glass plate was measured using ICP emission spectrometry.

[0063] Then, end portions of the two quartz glass plates were heated, and were pressed at 5 kg/cm.sup.2 for 1 hour when the temperature reached 1,700 C., to fuse the end portions, thereby preparing a sample.

[0064] As illustrated in FIG. 3, a load was applied to a fused portion of the obtained sample, and the breaking strength was measured and evaluated by a three-point bending test (JIS1601:2008). As a result, the breaking strength is 135 MPa or more, which is good as strength, and is described as A in Table 1.

[0065] In Table 1, since the breaking strength of the quartz glass member itself is 135 MPa, the breaking strength of 135 MPa or more is higher than the breaking strength of the quartz glass member itself, and thus is denoted by A. In addition, the breaking strength of less than 135 MPa is smaller than the breaking strength of the quartz glass itself, and thus is denoted by C.

[0066] As illustrated in FIG. 4, the length before fusion and the length after fusion (measured by a caliper) in a direction perpendicular to a pressing direction at the time of fusion of the quartz glass plates were compared, and a deformation amount was calculated to evaluate the thermal deformation. As a result, the deformation amount is 2.5 mm, which is small and good, and is described as A in Table 1.

[0067] In Table 1, a case where the deformation amount is 0 mm to 3.0 mm is denoted by A, and a case where the deformation amount exceeds 3.0 mm is denoted by B.

[0068] As illustrated by FIG. 5, in the fused portion, an area of one devitrified portion X having the maximum area among the devitrified portions X was measured by a microscope. In addition, an area occupancy ratio (%) of a total area of the devitrified portions to an area of the fused portion was measured.

[0069] As a result, the area of one devitrified portion X having the maximum area among the devitrified portions X is 1.62 mm.sup.2. The area occupancy ratio (%) of the total area of the devitrified portions to the area of the fused portion is 9%.

[0070] As illustrated in FIG. 6, the volume occupancy ratio (%) of the total volume of the devitrified portions Y per unit volume in the main body was measured by a microscope and visual observation. As a result, the volume occupancy ratio (%) of the devitrified portion Y is 0.015%.

Example 2

[0071] In Example 2, a quartz glass plate (Al: 18 ppm by weight, Ca: 1.0 ppm by weight, Mg: 0.1 ppm by weight, Na: 0.1 ppm by weight) was used. No devitrification was observed in two quartz glass plates. The content of each element in the quartz glass plate was measured using ICP emission spectrometry.

[0072] Then, end portions of the two quartz glass plates were heated, and were pressed at 5 kg/cm.sup.2 for 1 hour when the temperature reached 1,300 C., to fuse the end portions, thereby preparing a sample.

[0073] A fused portion of the obtained sample was subjected to the same measurement and evaluation as in Example 1. The results are shown in Table 1.

Example 3

[0074] In Example 3, a quartz glass plate (Al: 5 ppm by weight, Ca: 1.0 ppm by weight, Mg: 0.1 ppm by weight, Na: 0.1 ppm by weight) was used. No devitrification was observed in two quartz glass plates. The content of each element in the quartz glass plate was measured using ICP emission spectrometry.

[0075] Then, end portions of the two quartz glass plates were heated, and were pressed at 10 kg/cm.sup.2 for 1 hour when the temperature reached 1,300 C., to fuse the end portions, thereby preparing a sample.

[0076] A fused portion of the obtained sample was subjected to the same measurement and evaluation as in Example 1. The results are shown in Table 1.

Example 4

[0077] In Example 4, a quartz glass plate (Al: 25 ppm by weight, Ca: 1.0 ppm by weight, Mg: 0.1 ppm by weight, Na: 0.1 ppm by weight) was used. No devitrification was observed in two quartz glass plates. The content of each element in the quartz glass plate was measured using ICP emission spectrometry.

[0078] Then, end portions of the two quartz glass plates were heated, and were pressed at 10 kg/cm.sup.2 for 1 hour when the temperature reached 1,700 C., to fuse the end portions, thereby preparing a sample.

[0079] A fused portion of the obtained sample was subjected to the same measurement and evaluation as in Example 1. The results are shown in Table 1.

Comparative Example 1

[0080] In Comparative Example 1, a quartz glass plate (Al: 26 ppm by weight, Ca: 1.0 ppm by weight, Mg: 0.1 ppm by weight, Na: 0.1 ppm by weight) was used. No devitrification was observed in two quartz glass plates. The content of each element in the quartz glass plate was measured using ICP emission spectrometry.

[0081] Then, end portions of the two quartz glass plates were heated at 1,700 C. for 1 hour, and were pressed at 0.01 kg/cm.sup.2 for 1 hour to fuse the end portions, thereby preparing a sample.

[0082] A fused portion of the obtained sample was subjected to the same measurement and evaluation as in Example 1. The results are shown in Table 1.

Comparative Example 2

[0083] In Comparative Example 2, the quartz glass plate used in Example 1 was used, and end portions of two quartz glass plates were heated at 1,700 C. for 1 hour and were pressed at 0.01 kg/cm.sup.2 for 1 hour to fuse the end portions, thereby preparing a sample.

[0084] A fused portion of the obtained sample was subjected to the same measurement and evaluation as in Example 1. The results are shown in Table 1.

Comparative Example 3

[0085] In Comparative Example 3, the quartz glass plate used in Example 1 was used, and end portions of two quartz glass plates were heated at 1,800 C. and were pressed at 5 kg/cm.sup.2 for 1 hour, but a shape of the quartz glass plate cannot be maintained, and a sample cannot be manufactured.

Comparative Example 4

[0086] In Comparative Example 4, the quartz glass plate used in Example 1 was used, and end portions of two quartz glass plates were heated at 900 C. and pressed at 5 kg/cm.sup.2 for 1 hour, but the quartz glass plates were not fused.

[0087] Except for Comparative Examples 3 and 4, results of Examples 1 to 4 and Comparative Examples 1 and 2 are shown in Table 1.

[0088] As described above, in Evaluation 1 (breaking strength) in Table 1, A indicates a breaking strength of 135 MPa or more, and C indicates a breaking strength of less than 135 MPa. In Evaluation 2 (thermal deformation), A indicates a deformation amount of 0 mm to 3.0 mm, and B indicates a deformation amount exceeding 3.0 mm.

TABLE-US-00001 TABLE 1 Other than Fused portion fused Maximum cross- portion Evaluation 2 sectional area Area Volume Evaluation 1 Thermal Fusion Fusion (mm.sup.2) of one occupancy occupancy Strength deformation temperature pressure devitrification ratio (%) ratio (%) (MPa) (mm) Comparative 1,700 0.01 1.8 10 0.015 58 C 2.3 A example 1 Comparative 1,700 0.01 1.76 11 0.015 20 C 2.3 A example 2 Example 1 1,700 5 1.62 9 0.015 135 A 2.5 A Example 2 1,300 5 0.0078 10 0.015 138 A 0.5 A Example 3 1,300 10 0.0078 0.001 0.015 139 A 0.9 A Example 4 1,700 10 1.76 10 0.018 137 A 3.6 B

[0089] As shown in Table 1, it is confirmed that in order to ensure the necessary breaking strength and sufficiently suppress the thermal deformation, the maximum cross-sectional area of one devitrification in the fused portion is 1.76 mm.sup.2 or less, and the area occupancy ratio of the total area of the devitrified portions is 10% or less.