Quartz glass crucible and method for manufacturing the same

Abstract

To provide a quartz glass crucible capable of reducing an impurity dissolved in a silicon melt to obtain a high-pure silicon single crystal in a single crystal lifting treatment, and a manufacturing method of the same.SOLUTION: A quartz glass crucible has a transparent inner layer 4, at least one outer layer 2 arranged in an outer side of the transparent inner layer 4. The transparent inner layer 4 contains Fe, Ni, Cr, and Cu, of which content is lowest on a surface and is maximum at a depth of 20-40 μm from the surface. A manufacturing method of the quartz glass crucible has the steps of: producing a quartz glass crucible before a purification treatment, the quartz glass crucible having a transparent inner layer 4 and at least one outer layer 2 that is arranged outside the transparent inner layer 4; and performing the purification treatment where the quartz glass crucible before the purification treatment is heated to a temperature of 1000-1300°C from the transparent inner layer 4 side, a halogen gas is supplied for a predetermined time to the transparent inner layer 4 side to eliminate a metal impurity by reacting the halogen gas with a surface of the transparent inner layer 4.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a quartz glass crucible for pulling a silicon single crystal for pulling a single crystal by the Czochralski method (hereinafter referred to as the "CZ method").

Background Art

[0002] The quartz glass crucible used for pulling a silicon single crystal is a quartz member for containing a silicon melt, and the inner surface of the crucible in contact with the melt needs to be a high-purity transparent layer. On the other hand, on the outer surface side of the crucible, generally, an opaque outer layer containing a large amount of metal elements other than Si is formed for the purpose of reducing costs and improving high-temperature mechanical properties.

[0003] By the way, in order to purify the quartz member, for example, as disclosed in Patent Document 1, there is a method of exposing it to a halogen gas such as hydrogen chloride to remove metal impurities. In the method disclosed in Patent Document 1, after etching 30 μm or more from the surface layer of the quartz member with an HF solution, it is treated with a halogen gas at 400°C to 1300°C to remove the contained metal impurities.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the method disclosed in Patent Document 1, the quartz member is heated to a high temperature in order to enhance reactivity. Usually, a high temperature of 1000°C or more is suitable, but there is a risk that quartz may soften at around 1500°C, and about 1300°C becomes the upper limit value of the treatment temperature. When heating up to this temperature, usually, the heat source is arranged near the side wall of the heating furnace. Here, when the quartz member is a quartz glass crucible, the crucible will be heated from its outer surface side. Then, a temperature gradient will occur in the crucible where the outside is at a high temperature and the inner surface side is at a low temperature. That is, the opaque outer layer becomes hotter than the transparent inner layer that is desired to be highly purified.

[0006] However, when the opaque outer layer becomes hot, the diffusion rate of elements at high temperatures increases, and there is a problem that metal impurities contained in the opaque outer layer diffuse into the transparent inner layer. Also, since the formation of a high-purity layer by a halogen gas also depends on the element diffusion rate, there is a problem that an environment where metal impurities diffuse from the hotter outer layer side of the crucible cannot form a high-purity layer with a sufficient thickness.

[0007] The present invention has been made under the above circumstances, and has a high-purity layer with a sufficient thickness on the inner layer surface, and in the single crystal pulling process, can reduce impurities that dissolve in the silicon melt, and aims to provide a quartz glass crucible capable of obtaining a high-purity silicon single crystal and a method for manufacturing the same.

Means for Solving the Problems

[0008] The quartz glass crucible according to the present invention made to solve the above problems is a quartz glass crucible for pulling a single crystal, and has a transparent inner layer and at least one outer layer arranged outside the transparent inner layer. The transparent inner layer is characterized by having a distribution where the contents of Fe, Ni, Cr, and Cu are the smallest on the surface and reach a maximum at a depth of 20 to 40 μm from the surface. In addition, in the transparent inner layer, the content of Fe is 10 ppb or less, and the contents of Ni, Cr, and Cu are 1 ppb or less in the range from 10 μm from the surface to 30 μm from the surface.

[0009] According to such a configuration, in the quartz glass crucible having a transparent inner layer, the metal impurity content is the lowest on the surface of the transparent inner layer, and has a maximum value of the metal impurity content at a depth of 20 to 40 μm from the surface of the transparent inner layer. That is, a highly purified layer with a sufficient thickness is formed on the surface of the transparent inner layer. Thereby, in the single crystal pulling process, impurities that dissolve in the silicon melt can be reduced, and it becomes possible to obtain a high-purity silicon single crystal.

[0010] Further, the method for manufacturing a quartz glass crucible according to the present invention made to solve the above problems is the method for manufacturing the quartz glass crucible, including a step of manufacturing a quartz glass crucible before high-purity treatment having a transparent inner layer and at least one outer layer disposed outside the transparent inner layer, and a step of heating the quartz glass crucible before high-purity treatment from the transparent inner layer side to a temperature of 1000°C to 1300°C, and supplying a halogen gas to the transparent inner layer side for a predetermined time to perform a high-purity treatment of reacting the halogen gas with the surface of the transparent inner layer to remove metal impurities.

[0011] According to such a method, the quartz glass crucible can be obtained by heating the quartz glass crucible before high-purity treatment from its inner surface side and supplying a halogen gas to perform a high-purity treatment. In this high-purity treatment, since the inner layer side becomes high temperature and the outer layer side becomes lower temperature, diffusion of metal impurities from the opaque outer layer with a large amount of metal impurities can be suppressed, and the high-purity treatment can be efficiently performed. At this time, heating from the outside of the quartz glass crucible may be used in combination.

Effect of the Invention

[0012] According to the present invention, it is possible to provide a quartz glass crucible having a highly purified layer with a sufficient thickness on the inner layer surface, capable of reducing impurities that dissolve in the silicon melt in the single crystal pulling process, and obtaining a high-purity silicon single crystal, and a method for manufacturing the same.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of a quartz glass crucible and a method for manufacturing the same according to the present invention will be described with reference to the drawings. Figure 1 is a cross-sectional view of a quartz glass crucible 1 according to the present invention. Figure 2 is a partially enlarged cross-sectional view of the quartz glass crucible of Figure 1. This quartz glass crucible 1 is used, for example, in a single crystal pulling apparatus (not shown), and is used in a state of being held by a carbon susceptor (not shown) inside the apparatus. That is, in the single crystal pulling apparatus, raw material silicon is melted in the quartz glass crucible 1, and a silicon single crystal is pulled from the melt.

[0015] The quartz glass crucible 1 is formed, for example, to have a diameter (aperture) of 32 inches, and has a bottom 9 having a predetermined curvature (first curvature), a bottom corner 8 formed around the bottom 9 and having a predetermined curvature (second curvature), and a side portion 7 extending upward from the bottom corner 8. As shown in Figure 1, on the outermost side of the side portion 7, an outer layer 2 is formed from the upper end 6 of the crucible to below the side portion 7. The outer layer 2 is formed of an Al-added quartz glass layer to which, for example, Al is added as a crystallization accelerator. formed by the added quartz glass layer.

[0016] Specifically, before use (before high-temperature heating), in the outer layer 2 (crystallization accelerator addition layer), for example, a primary additive raw material with an Al concentration of 100 ppm is dispersed in the glass, and the Al concentration in the outer layer 2 is 25 ppm. That is, the vitrifying part and the crystallizing part are formed in a state of being mixed in the layer. After use (after high-temperature heating), the outer layer 2 does not become a single layer of crystals, but the primary additive raw material crystallizes, and the glass part and the crystallized part are mixed.

[0017] An opaque intermediate layer 3 made of natural raw material quartz glass is formed inside the outer layer 2. Furthermore, inside this intermediate layer 3, a transparent inner layer 4 made of high-purity synthetic raw material quartz glass (or natural raw material quartz glass) that comes into contact with molten silicon during the pulling of a silicon single crystal is formed.

[0018] Here, "opaque" means that a large number of air bubbles (pores) are present in the quartz glass, and it appears cloudy. Also, the natural quartz layer means a silica glass layer manufactured by melting natural raw materials such as quartz crystals, and the synthetic quartz layer means a silica glass layer manufactured by melting synthetic raw materials synthesized by, for example, the hydrolysis of silicon alkoxide.

[0019] Also, as described above, the outer layer 2 is not formed over the entire outside of the crucible. That is, the outer layer 2 is not formed at the crucible bottom corner 8 and the crucible bottom 9, but is formed only on the side portion 7. That is, as shown in the figure, the crucible bottom corner 8 and the crucible bottom 9 are formed in a two-layer structure composed of an opaque outer layer 5 made of natural raw material quartz glass continuously formed from the opaque intermediate layer 3 on the side portion 7 and a transparent inner layer 4 made of synthetic raw material quartz glass (or natural raw material quartz glass). This is to soften the bottom corner 8 and the bottom 9 (opaque outer layer 5) at the initial stage of the start of single crystal pulling and bring them into close contact with the carbon susceptor that supports the crucible 1.

[0020] Further, as shown in FIG. 2, the outer layer 2 is formed such that the thickness dimension et1 at the crucible side portion 7 is, for example, 1 mm or more and 40 mm or less. This is because if the thickness is greater than 40 mm, it is difficult to obtain adhesion to the carbon crucible due to the crystallization layer being too thick, and if it is less than 1 mm, it is difficult to contribute to improving durability.

[0021] Further, the Al concentration of the Al-added quartz glass of the outer layer 2 is formed in the range of 10 to 300 ppm, and the particle size distribution of each crystal grain is such that 90% of all the crystal grains are included in the range of 50 to 400 μm. Since crystal grains are distributed in the glass layer in the outer layer 2 in this way, the tensile stress generated between the outer layer 2 and the intermediate layer 3, which is a glass layer, can be dispersed into a slight force per crystal grain unit, preventing the generation of cracks.

[0022] Further, the opaque intermediate layer 3 made of natural raw material quartz glass has a thickness dimension mt1 at the crucible side portion 7 of 3 mm or more. Further, the thickness dimension mt2 of the opaque outer layer 5 at the crucible bottom corner 8 continuously formed from the opaque intermediate layer 3 is formed to be 6 mm or more, and the thickness dimension mt3 of the opaque outer layer 5 at the crucible bottom 9 is formed to be 6 mm or more.

[0023] This is because if the thickness of the opaque intermediate layer 3 in the three-layer portion is less than 3 mm, the effect of preventing the scattering of the crystallization accelerator compound of the opaque intermediate layer 3 due to the irregular flow of the arc flame during the melting of the quartz glass powder is easily reduced, and there is a risk that the crystallization accelerator compound of the outer layer 2 passes through the opaque intermediate layer 3 and mixes into the transparent inner layer 4, increasing the crystallization accelerator concentration of the transparent inner layer 4. Further, if the thickness dimension mt2 of the opaque outer layer 5 at the crucible bottom corner 8 and the thickness dimension mt3 of the opaque outer layer 5 at the crucible bottom 9 are less than 6 mm, it is difficult to obtain sufficient durability.

[0024] Further, the transparent inner layer 4 is a transparent layer that is formed by melting synthetic raw material quartz glass (or natural raw material quartz glass) and then has a reduced content of metal impurities such as Fe, Ni, Cr, and Cu and substantially no bubbles by the high-purity treatment described later. Specifically, (as shown in the graph of Fig. 5(b)), the content of metallic impurities such as Fe, Ni, Cr, and Cu is the lowest on the surface of the transparent inner layer 4, and the content of the metallic impurities gradually increases from the surface of the transparent inner layer 4 toward the inner side, reaching a maximum at a depth of 20 μm to 40 μm, and then gradually decreasing as the depth increases further. That is, as shown in Fig. 2, a highly purified layer 4a with a sufficient thickness in which the content of metallic impurities is significantly reduced from the surface of the transparent inner layer 4 to a depth of 10 μm from the surface or to a depth of 30 μm from the surface is formed.

[0025] More specifically, at a depth of 10 μm from the surface of the transparent inner layer 4 to a depth of 30 μm from the surface, the content of Fe is set to 10 ppb or less, and the contents of Ni, Cr, and Cu are formed to be 1 ppb or less. Thus, in the transparent inner layer 4, a highly purified layer 4a with a reduced content of metallic impurities by a highly purified treatment is formed on its surface. Thereby, in the single crystal pulling process, the impurities dissolved in the silicon melt can be reduced, and it becomes possible to obtain a high-purity silicon single crystal. In addition, in the transparent inner layer 4, the thickness dimension it1 at the side portion 7 of the crucible, the thickness dimension it2 at the corner 8 of the bottom of the crucible, and the thickness dimension it3 at the bottom 9 of the crucible are all formed to have a thickness of, for example, 3 mm or more.

[0026] Next, a method for manufacturing the quartz glass crucible 1 having the above structure will be described. First, a quartz glass crucible before the highly purified treatment is manufactured using a quartz glass crucible manufacturing apparatus 10 as shown in Fig. 3. The crucible forming mold 11 of the quartz glass crucible manufacturing apparatus 10 is composed of, for example, an inner member 12 made of a gas-permeable member such as a mold having a plurality of through holes drilled therein or a highly purified porous carbon mold, and a holding body 14 provided with a ventilation portion 13 on its outer periphery for holding the inner member 12.

[0027] Also, a rotary shaft 15 connected to a rotating means (not shown) is fixed to the lower part of the holder 14, and the crucible forming die 11 is rotatably supported. The ventilation part 13 is connected to an exhaust passage 17 provided at the center of the rotary shaft 15 through an opening 16 provided in the lower part of the holder 14, and this exhaust passage 17 is connected to a decompression mechanism 18. An arc electrode 19 for arc discharge, an Al additive raw material supply nozzle 20, a natural quartz powder supply nozzle 22, and a high-purity synthetic quartz powder supply nozzle 23 are provided above the inner member 12 so as to face it.

[0028] The Al-added quartz powder used for the outer layer 2 can be obtained as follows. For example, an aqueous solution of aluminum nitrate (Al(NO3)3) prepared by dissolving aluminum nitrate in water in an amount such that the Al concentration in the quartz powder is, for example, 100 ppm is added to the quartz powder and stirred. After stirring, heat treatment is performed at 800 to 1100 °C for the purpose of dehydration and acid removal. Thereby, a primary additive raw material with a high Al concentration can be obtained. Next, the primary additive raw material is mixed with the same amount of quartz powder to obtain a secondary additive raw material in which the primary additive raw material is uniformly dispersed and the Al concentration is, for example, 25 ppm. This is used as the Al-added quartz powder to be supplied to the outer layer 2.

[0029] In the Al-added quartz powder, 90% or more of the primary additive raw material C1 is contained in the range of the overall average particle size ±25%. Thereby, it is possible to prevent the primary additive raw material from segregating due to vibration during transportation or stirring when the Al-added quartz powder is formed into a crucible shape. Also, in the above example, the primary additive raw material was mixed with the same amount of quartz powder to form the Al-added quartz powder, but the content ratio of the primary additive raw material in the Al-added quartz powder is desirably in the range of 1 to 50%, whereby it is possible to make a state in which non-added quartz powder is interposed between the primary additive raw materials.

[0030] When manufacturing a quartz glass crucible using the thus obtained Al-added quartz powder with a quartz glass crucible manufacturing apparatus 10, a rotation drive source (not shown) is operated to rotate the rotary shaft 18 in the direction of the arrow, thereby rotating the crucible forming die 11 at high speed. Next, Al-added silica powder (Al concentration: 25 ppm) is supplied from the Al-added raw material supply nozzle 20 into the crucible forming mold 11. The supplied Al-added silica powder is pressed against the inner surface side of the inner member 12 by centrifugal force and formed as the outer layer 2. At this time, the primary added raw material in the outer layer 2 is in a state of being dispersed in the silica powder.

[0031] Here, as described with reference to FIG. 2, the position of the lower end of the outer layer 2 is determined, and the bottom corner and the bottom are removed. That is, the outer layer 2 is removed from the bottom corner to the bottom of the quartz glass crucible 1 to be manufactured.

[0032] Next, natural silica powder is supplied from the natural silica powder supply nozzle 22 so that an opaque intermediate layer 3 having a thickness of 3 mm or more is formed on the inner surface side of the outer layer 2, and an opaque outer layer 5 having a thickness of 6 mm or more is formed at the bottom corner and the bottom. The supplied natural silica powder is pressed against the inner surface side of the outer layer 2 and the bottom of the inner member 12 by centrifugal force and formed as a molded body of the opaque intermediate layer 3 and the opaque outer layer 5.

[0033] Next, high-purity synthetic silica powder having a metal impurity content of 1 ppm or less for each of Na, K, and Al is supplied from the high-purity synthetic silica powder supply nozzle 23 so that a transparent layer having a thickness of 3 mm or more is formed on the inner surface side of the opaque intermediate layer 3 and the opaque outer layer 5. The supplied high-purity synthetic silica powder is pressed against the inner surface side of the opaque intermediate layer 3 and the opaque outer layer 5 by centrifugal force and formed as a molded body of the transparent inner layer 4.

[0034] In this way, a crucible molded body of the outer layer 2 in which the Al-added raw material is dispersed, the opaque intermediate layer 3, the opaque outer layer 5, and the transparent inner layer 4 is obtained. Furthermore, the inside of the inner member 12 is depressurized by the operation of the decompression mechanism 18, an arc electrode 19 is energized to heat from the inside of the crucible molded body, and the transparent inner layer 4, the opaque intermediate layer 3, the opaque outer layer 5, and the outer layer 2 of the crucible molded body are melted to manufacture a quartz glass crucible 1A before the high-purity treatment.

[0035] Next, a purification process is performed on the quartz glass crucible 1A before the purification process. FIG. 4 is a cross-sectional view schematically showing the purification apparatus. This purification apparatus 30 includes a chamber 31 for accommodating the quartz glass crucible 1A and a mounting table 32 for mounting the quartz glass crucible 1A in the chamber 31. As shown in the drawing, the quartz glass crucible 1A is mounted upside down so that its opening abuts against the mounting table 32.

[0036] The purification apparatus 30 also includes a heater 33 for heating the quartz glass crucible 1A, a thermocouple 34 for measuring the heating temperature, a gas supply unit 35 for supplying a halogen gas into the chamber, and a gas exhaust unit 36 for exhausting the atmosphere in the chamber. As shown in the drawing, the heater 33, the thermocouple 34, the gas supply unit 35, and the gas exhaust unit 36 are arranged inside the crucible 1A and are configured such that the inner surface of the crucible is exposed to the halogen gas at a high temperature.

[0037] Specifically, for example, a quartz glass crucible 1A with a diameter of 32 inches is mounted upside down on the mounting table 32 in the chamber 31 as shown in FIG. 4. At this time, the heater 33, the thermocouple 34, the gas supply unit 35, and the gas exhaust unit 36 are arranged inside the crucible 1A.

[0038] Next, the heater 33 is driven and heated until the temperature of the thermocouple 34 reaches, for example, 1200°C. Then, hydrogen chloride gas is flowed as a halogen gas at 2 L / min and argon gas at 3 L / min by the gas supply unit 35, and the state is maintained for 12 hours. Thereafter, the driving of the heater 33 is stopped and the chamber 31 is exhausted by the gas exhaust unit 36, and the crucible is taken out from the chamber 31 to obtain the purified quartz glass crucible 1.

[0039] In this purification method, when the temperature of the crucible inner surface (the surface of the transparent inner layer 4) reaches a temperature suitable for the purification treatment (for example, 1200°C), the temperature of the crucible outer surface is lower than that in the case of using a normal furnace that heats from the crucible outer surface side. Therefore, the diffusion of metal impurities from the opaque outer layer 2 with a high content of metal impurities to the transparent inner layer 4 is suppressed, and it becomes possible to efficiently purify the surface of the transparent inner layer 4.

[0040] In addition, for the quartz glass crucible 1A before the purification treatment, depending on its manufacturing method, as shown in the graph of Fig. 5(a) (the vertical axis is the metal impurity content and the horizontal axis is the depth from the surface of the crucible inner layer), there is a possibility that impurities are unevenly distributed on the surface of the transparent inner layer 4. When the purification treatment is applied to such a quartz glass crucible 1A, as shown in the graph of Fig. 5(b), the metal impurities near the surface diffuse and are removed to the inner side. Therefore, the metal impurity content can be minimized on the surface, and the maximum value of the metal impurity content on the surface side can be moved to a predetermined depth from the inner surface.

[0041] The depth of the maximum value depends on the impurity distribution and purification conditions of the original quartz glass crucible 1A. However, since the impurity amount gradient in a deeper part becomes gentle, the depth at which a clear maximum value can be obtained is 20 to 40 μm.

[0042] As described above, according to this embodiment, in the quartz glass crucible 1 having the transparent inner layer 4, the metal impurity content is the lowest on the surface of the transparent inner layer 4, and there is a maximum value of the metal impurity content at a depth of 20 to 40 μm from the surface of the transparent inner layer 4. That is, a highly purified layer 4a with a sufficient thickness is formed on the surface of the transparent inner layer 4. Thereby, in the single crystal pulling process, the impurities dissolved in the silicon melt can be reduced, and it becomes possible to obtain a high-purity silicon single crystal. The quartz glass crucible 1 is obtained by performing a purification treatment on the quartz glass crucible 1A before the purification treatment, heating it from the inner surface side and supplying a halogen gas. In this purification treatment, since the inner layer 4 side becomes high temperature and the intermediate layer 3 and the outer layer 5 side become lower temperature, diffusion of metal impurities from the opaque intermediate layer 3 and the opaque outer layer 5 with a large amount of metal impurities can be suppressed, and the purification treatment can be efficiently performed.

[0043] In addition, in the above embodiment, the crucible side part having a three-layer structure and the manufacturing method thereof have been described as an example. However, in the present invention, it is not limited thereto, and for example, it can also be applied to a two-layer quartz glass crucible having a transparent inner layer and an opaque outer layer.

Example

[0044] Subsequently, the quartz glass crucible and the manufacturing method thereof according to the present invention will be further described based on examples. In this example, the purification treatment of the quartz glass crucible having the configuration shown in the above embodiment was performed to verify the effects of the present invention.

[0045] (Example 1) Using the purification treatment apparatus shown in FIG. 4, a purification treatment was performed on a 32-inch quartz glass crucible. That is, the crucible was placed upside down on the mounting table in the chamber and heated to 1200° C. by a carbon heater disposed inside the crucible. Then, hydrogen chloride was flowed at 2 L / min and argon gas was flowed at 3 L / min, and the state was maintained for 12 hours to perform the purification treatment.

[0046] The inner surface of the crucible after this purification treatment was etched with hydrofluoric acid by 10 μm up to 50 μm and analyzed. As a result, the content of Fe in the outermost surface was 8 ppb or less, and the contents of Ni, Cr, and Cu were 1 ppb or less. Also, from the surface to a depth of 30 μm, the content of Fe increased to about 50 ppb, and the contents of Ni, Cr, and Cu increased to about 10 ppb. Further, at a depth of 50 μm from the surface, Fe was about 30 ppb, and the contents of Ni, Cr, and Cu turned to decrease to about 5 ppb.

[0047] (Comparative Example 1) A 32-inch quartz glass crucible was placed inside the chamber, and the crucible was heated to 1200 °C with a carbon heater from the outside of the crucible. Also, a pipe was installed so that gas could be supplied inside the crucible. Then, hydrogen chloride was flowed at 2 L / min and argon gas was flowed at 3 L / min, and the state was maintained for 12 hours to perform a high-purification treatment. After this high-purification treatment, the inner surface of the crucible was melted with hydrofluoric acid by 10 μm up to 50 μm and analyzed. As a result, the outermost surface had an Fe content of about 100 ppb, and the contents of Ni, Cr, and Cu were 1 to 20 ppb. Also, the metal impurity content decreased as it became deeper from the surface, and at a depth of 50 μm from the surface, Fe was about 30 ppb and the contents of Ni, Cr, and Cu were about 5 ppb.

[0048] As a result of the examples, it was confirmed that according to the method for manufacturing a quartz glass crucible of the present invention, the metal impurity content on the inner layer surface can be minimized in the range from 10 μm from the surface to 30 μm from the surface, and high purity can be achieved.

Explanation of Signs

[0049] 1 Quartz glass crucible 2 Outer layer 3 Opaque intermediate layer 4 Transparent inner layer 5 Opaque outer layer 7 Side part 8 Bottom corner 9 Bottom 10 Quartz glass crucible manufacturing apparatus 30 High-purification treatment apparatus

Claims

**Claim 1**: A method for manufacturing a quartz glass crucible for pulling a single crystal, comprising a transparent inner layer and at least one outer layer disposed outside the transparent inner layer, wherein the transparent inner layer has a distribution in which the contents of Fe, Ni, Cr, and Cu are the smallest at the surface and reach a maximum at a depth of 20 to 40 μm from the surface. A step of manufacturing a quartz glass crucible before purification treatment, which has a transparent inner layer and at least one outer layer disposed outside the transparent inner layer. A step of performing a purification treatment in which the quartz glass crucible before purification treatment is heated to a temperature of 1000 °C to 1300 °C from the transparent inner layer side, and a halogen gas is supplied to the transparent inner layer side for a predetermined time to react the halogen gas with the surface of the transparent inner layer to remove metal impurities. A method for manufacturing a quartz glass crucible, characterized by comprising the above steps. **Claim 2**: The method for manufacturing a quartz glass crucible according to claim 1, wherein in the transparent inner layer, the content of Fe, Ni, Cr, and Cu is such that the content of Fe is 10 ppb or less and the contents of Ni, Cr, and Cu are 1 ppb or less from the surface to a depth of 10 μm from the surface to 30 μm from the surface.

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