JP4533188B2 - Crystal manufacturing apparatus and crystal manufacturing method - Google Patents

Description

The present invention is, you about the crystal manufacturing apparatus and a crystal manufacturing method for manufacturing a single crystal of calcium fluoride.

With the demand for miniaturization of semiconductor devices, it is necessary to increase the exposure resolution of the exposure apparatus, as a method therefor, a short wavelength light such as ArF excimer laser (wavelength: about 193 nm) and F ₂ laser (wavelength: about 157 nm) Proposed to use optical elements such as lenses and diffraction gratings made of calcium fluoride (CaF ₂ ) as a glass material with excellent transmittance for such short-wavelength light in the exposure optical system. Has been.

  Parameters for evaluating the optical characteristics of optical materials such as lenses include internal durability, laser durability that represents the change in transmittance when laser light is continuously received, and the refractive index of the lens, regardless of location. There are refractive index uniformity (homogenity), birefringence, polishing (or processing) accuracy, and the like, and high quality is required for calcium fluoride used in an exposure apparatus.

The calcium fluoride single crystal is generally produced by a crucible descent method also known as “vertical Bridgman method” (see, for example, Patent Documents 1 to 3). In this method, a raw material of a crystalline substance is placed in a crucible, and the raw material melted by heating with a heater or the like is crystallized by cooling while lowering the crucible.
US Pat. No. 2,149,076 US Pat. No. 2,214,976 JP 2003-201195 (paragraph 0002 etc.)

  Conventionally, the material of the crucible used in the crystal manufacturing apparatus by the crucible lowering method is not particularly limited, and generally, high-purity carbon that can withstand the melting temperature and has few impurities is used. However, it has not been possible so far to obtain a high-quality and large-diameter single crystal that satisfies the specifications of an exposure apparatus using an excimer laser light source simply because the material of the crucible is simply high purity. That is, when a single crystal is grown using a conventional crystal growth apparatus proposed in Patent Documents 1 to 3, only a crystal having a high dislocation density, that is, a crystal having a low quality can be obtained.

  This is considered to be because the crystal part solidified during crystal growth is in contact with the inner wall of the crucible. Since calcium fluoride shrinks when solidified, it separates from the inner wall of the crucible, and a space is generated between the crystal and the inner wall of the crucible. However, in the conventional crystal manufacturing apparatus, since the pressure in the space is not so high that this space is always maintained, the crystal continues to grow while frequently contacting the inner wall of the crucible. That is, it is considered that when the crystal comes into contact with the crucible at a high temperature immediately after solidification, a thermal stress or a mechanical stress is applied to the crystal, and as a result, dislocation occurs and grows.

  FIG. 3 shows a topographic image of a crystal manufactured by a conventional crystal manufacturing apparatus. From this image, it can be seen that the size of the slightly inclined regions (subgrains) is very fine and the crystallinity is extremely poor.

The present invention has as one object of thereof is to provide a manufactured in terms of lack advantageous crystal manufacturing apparatus and a crystal manufacturing method of the dislocations in the crystal.

The crystal production apparatus according to one aspect of the present invention includes a heater, a crucible around the heater, and an elevating unit that moves the crucible with respect to the heater, and evacuates a space in which the crucible is stored, The calcium fluoride stored in the crucible is melted by heating with a heater, and the molten calcium fluoride is cooled by moving the crucible by the elevating part to lower the temperature of the crucible, thereby growing a single crystal of calcium fluoride. Let And the crucible is such that the pressure in the space formed between the inner wall of the crucible and the single crystal is higher than the pressure in the space above the molten calcium fluoride and exhausted by vacuum. The gas permeability of the portion where the film of pyrolytic carbon or glassy carbon is formed and the single crystal exists inside is 1 × 10 ⁻⁴ cm ² / s or less .
In another aspect of the present invention, there is provided a method for producing a crystal, wherein a space for housing a crucible is evacuated, a heater is disposed around the crucible, and heated by the heater to be stored in the crucible. And a step of moving the crucible with respect to the heater to lower the temperature of the crucible and cooling the molten calcium fluoride to grow a single crystal of calcium fluoride. The crucible has a gas permeability of 1 × 10 ⁻⁴ cm ² / s or less at a portion where a film of pyrolytic carbon or glassy carbon is formed and a single crystal is present on the inside , and depending on the gas permeability The pressure in the space formed between the inner wall of the crucible and the single crystal is higher than the pressure in the space above the molten calcium fluoride and exhausted by vacuum.

According to the present invention, it is possible to provide a manufactured in terms of lack advantageous crystal manufacturing apparatus and a crystal manufacturing method of the dislocations in the crystal.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a schematic configuration of a crystal manufacturing apparatus 100 that is an embodiment of the present invention. The crystal manufacturing apparatus 100 grows a crystal (single crystal) by melting the raw material ID in the crucible 110 and then cooling it.

  The crystal manufacturing apparatus 100 includes a crucible 110, a support member 120, a crucible lifting / lowering unit 130, a heater 140, a thermocouple 150, a heat insulating member 160, and a housing 170.

  The substantially cylindrical crucible 110 is supported by a support member 120, and is housed in a growth furnace CGF configured by a substantially cylindrical heat insulating member 160 and a casing 170. The crucible 110 is heated by a heater 140 disposed along the periphery of the cylindrical surface. In addition, the crystal manufacturing apparatus 100 includes an exhaust device EM that decompresses or evacuates the growth furnace CGF.

The crucible 110 stores a raw material ID of a crystalline material (calcium fluoride in this embodiment). The crucible 110 melts the raw material ID, holds the melt (liquid part) ID _a , and further grows the crystal. Therefore, the crucible 110 does not react with the melt ID _a and has a low impurity content such as carbon or boron nitride. It is preferable that it is comprised. In addition, the crucible 110 having a value that can form a predetermined temperature gradient in the vertical direction, for example, 5 ° C./cm, on the single crystal whose thermal conductivity is to be grown is used.

  Furthermore, the crucible 110 has a storage chamber 114 in the lower part 112 for storing the seed crystal SC. A conical portion 116 described later is formed between the storage chamber 114 and the growth chamber formed thereabove. The crucible 110 is connected to the support member 120 at the lower part 112 and is installed at the center of the growth reactor CGF.

  Further, the crucible 110 has a conical portion 116 whose diameter decreases toward the lower side at the lower portion 112 where crystal growth starts. It is important that the inner surface shape of the crucible 110 for storing the raw material ID is a conical shape, and the outer surface shape of the lower portion 112 of the crucible 110 is not necessarily a conical shape as shown in FIG. The outer surface shape of the lower portion 112 of the crucible 110 may be a shape that does not affect the heat radiation space, for example, a cylindrical shape.

The outer surface of the crucible 110 has a thickness of about 40 microns and is coated with a carbonized film 117 made of pyrolytic carbon. Thereby, the gas permeability of the crucible 110 becomes 1 × 10 ⁻⁴ cm ² / s or less, and the wall portion of the crucible is compared with the conventional crucible (the gas permeability is about 1 × 10 ⁻¹ cm ² / s). The amount of gas that permeates is significantly reduced.

  In this embodiment, the carbonized film 117 is coated only on the outer surface of the crucible 110. However, even if a film is formed only on the inner surface of the crucible 110 or a film is formed on both the outer surface and the inner surface. Good. By forming a coating on both the outer and inner surfaces, the gas permeability can be further reduced. Further, it is important that the coating is applied to at least one of the outer surface and the inner surface of the portion where the melt exists in the crucible 110, and is not necessarily required on the upper portion of the crucible where no melt exists.

  Here, the relationship between the gas permeability of the crucible and the crystallinity will be described. FIG. 2 schematically shows the inside of the crucible 110 during crystal growth. The shape of the crucible 110 is simplified for explanation.

In the crucible 110, calcium fluoride ID _b of the solidified portion is contracted away from the crucible inner wall, air gap 182 is generated between the crystal ID _b and the crucible interior wall. At this time, the solidified crystal ID _b and the crucible 110 are connected via the curved melt ID _a . Next, let us look at the gas permeability above and below the melt ID _a .

First, above the melt ID _a , the lid 110a of the crucible 110 and the crucible main body are only coupled by a screwed structure, so that the gas in the space 180 formed above the melt ID _a is covered with the lid. It is easy to permeate through the gap between 110a and the crucible body.

On the other hand, in the portion below the melt ID _a , that is, the portion where the crystal ID _b exists, the dense carbonized film 117 is coated on the outer surface of the crucible 110, so that the gas is difficult to permeate. As a result, the pressure P2 in the gap 182 between the crystal ID _b and the inner wall of the crucible becomes higher than the pressure P1 in the gap 180 above the melt, and the meniscus shape of the curved melt ID _a and the gap 182 are stable. Maintained. By maintaining the gap 182, the crystal ID _b and the crucible inner wall are always in a non-contact state, and as a result, it is possible to suppress the occurrence of dislocations in the growing crystal.

In FIG. 1, the support member 120 penetrates the bottom of the housing 170 and the upper part reaches the growth reactor CGF. Support member 120 supports the weight of the melt IDa and crystal IDb in the crucible 110 and the crucible 110, thereby vertically moving the crucible 1 1 0 by being driven by the crucible elevating section 130. Further, the support member 120 can be driven by a rotation mechanism (not shown) to rotate the crucible 110. The crucible 110 is rotated to make the temperature of the crucible 110 uniform.

  The crucible lifting / lowering unit 130 includes a motor 132 connected to the support member 120 and a power source 134 that supplies electric power to the motor 132. By controlling energization from the power source 134 to the motor 132, the crucible 110 can be moved from the heating region of the heater 140 to the non-heating region, and the temperature of the crucible 110 can be gradually lowered.

  The heater 140 is arranged in a ring shape with respect to the cylindrical surface of the crucible 110, heats the raw material ID together with the crucible 110, and melts it. The heater 140 heats the crucible 110 with a uniform heating force along the vertical direction of the crucible 110. The heater 140 is made of graphite in this embodiment.

Further, as shown in FIG. 1, the heater 140 is composed of an upper heater 142 and a lower heater 144 in multiple stages. Thereby, the temperature in the growth furnace CGF can be precisely controlled. Specifically, the upper heater 142 is suitable for maintaining the temperature of the melt ID _a , and the lower heater 144 is suitable for holding the grown crystal (solid portion) ID _b . Set to temperature. Further, in the vicinity of the middle between the upper heater 142 and the lower heater 144, the inside of the crucible 110 is adjusted to be the melting point temperature of the raw material ID.

  The thermocouple 150 as a temperature sensor is disposed on the outer side surface of the upper heater 142 and the lower heater 144 and detects the temperature of the upper heater 142 and the temperature of the lower heater 144. The upper heater 142 and the lower heater 144 are thermally designed so as to have a uniform temperature distribution by controlling the current distribution within the upper heater 142 and the lower heater 144. .

  The heat insulating member 160 is disposed adjacent to the inner surface of the growth furnace CGF so as to surround the heater 140. The heat insulating member 160 is made of carbon whose inner surface is well polished, and protects the housing 170 from the heat of the heater 140.

  The case 170 blocks the atmosphere in the growth furnace CGF from the outside air during crystal growth, and maintains a reduced pressure or vacuum environment in the growth furnace CGF. In this embodiment, the casing 170 is configured by disposing a heat insulating material (not shown) in the double cylinder using a double cylinder made of stainless steel or the like.

The material of the crucible 1 1 0, open porosity may be a carbon of 10% or less. The crucible 110 may be filled with open pores with a carbonized material. Accordingly, if the gas permeability of the crucible 110 is 1 × 10 ⁻⁴ cm ² / s or less, it is not necessary to form a film on the crucible.

Furthermore, the gas permeability of the crucible is preferably 1 × 10 ⁻⁴ cm ² / s or less and 1 × 10 ⁻¹³ cm ² / s or more regardless of the presence or absence of the coating. The film formed on the crucible may be a carbonized film made of glassy carbon.

  In this embodiment, the case of producing a calcium fluoride single crystal has been described. However, the present invention can also be used for producing crystals other than the calcium fluoride single crystal.

(Experimental example)
Hereinafter, an example of a production experiment of calcium fluoride crystals using the crystal production apparatus 100 shown in FIG. 1 will be described. In the following, the crystal manufacturing method according to the embodiment of the present invention will be described together with the operation of the crystal manufacturing apparatus 100. FIG. 5 shows a flowchart for explaining a crystal manufacturing method 1000 according to an embodiment of the present invention.

In this experimental example, a graphite crucible 110 having a diameter of 300 mm was prepared, and the cone angle AG of the cone portion 116 was set to 60 degrees. The conical angle AG of the conical portion 116 is appropriately set depending on the material and size of the crystal to be grown, and is not limited to 60 degrees. Calcium fluoride used for the raw material ID is not a raw stone (natural fluorite), but a high-purity calcium fluoride powder that has been chemically synthesized by treating CaCO ₃ with hydrofluoric acid and then solidifying it. (That is, a purified product) or a pulverized product thereof was used. This is because high-purity calcium fluoride has a large volume reduction when melted, and the size of crystals obtained with respect to the size of the crucible 110 is remarkably reduced.

  5, first, a seed crystal SC having a {1 1 1} plane on the upper surface is stored in the storage portion 114 of the crucible 110 (step 1002).

  Next, the crushed raw material ID and scavenger are filled in the crucible 110 (step 1004). The amount of scavenger is preferably 0.01 wt% or more and 0.1 wt% or less with respect to the amount of the raw material ID. In this experimental example, the amount of scavenger was set to 0.01 wt% with respect to the raw material ID.

  The scavenger has a function of reducing calcium oxide (CaO) generated by the presence of moisture to calcium fluoride to calcium fluoride. As the scavenger, zinc fluoride, cadmium fluoride, manganese fluoride, bismuth fluoride, sodium fluoride, lithium fluoride, and the like, which are more easily bonded to oxygen than the growing fluoride, and easily decomposed and evaporated, are desirable. A substance that reacts with an oxide mixed in the fluoride raw material to become an oxide that is easily vaporized is selected, and zinc fluoride is particularly preferable.

Next, by operating the exhaust device EM, the growth furnace CGF is set to a vacuum degree of about 10 ⁻³ Pa to 10 ⁻⁴ Pa, the heater 140 is energized to heat the raw material ID in the crucible 110, and the crucible 110 The raw material ID filled in is completely melted (step 1006). Specifically, the temperature of the growth furnace CGF was controlled so that a part of the seed crystal SC and the raw material ID were melted, and the melt was held for 2 days.

  After melting and holding, the crucible 110 is gradually pulled down to cool the melted raw material ID and grow a calcium fluoride single crystal (step 1008). The crystal grows by further precipitating the crystal from the melt on the surface of the crystal grown near the melting temperature. In this experimental example, the temperature distribution of the entire growth furnace CGF was fixed, and the pulling speed of the crucible 110 was set to 0.25 mm / h to 1 mm / h. The length of the grown calcium fluoride single crystal was 100 mm to 300 mm, and the growth was performed over a period of about 400 hours to 1500 hours.

  Subsequently, the crystal-grown single crystal is heat-treated in an annealing furnace (annealing step) (step 1010). The annealing step is a step of heat-treating the grown calcium fluoride single crystal to remove strain that causes crystal cracking. The grown single crystal is put in a crucible housed in an annealing furnace. In the annealing step, the crucible is heated to about 1080 ° C. so as to remove the strain of the calcium fluoride crystal while it remains solid.

  Thereafter, a single crystal is cut out from the grown calcium fluoride crystal (step 1012).

  FIG. 4 shows a topographic image of the calcium fluoride single crystal produced in this experimental example. Compared with the calcium fluoride single crystal of FIG. 3 manufactured by the conventional manufacturing method, it can be seen that the size of the subgrain is large and the crystallinity is very good.

Thus, in the crystal manufacturing apparatus 100 and the crystal manufacturing method 1000, the outer surface of the crucible 110 is coated with the dense carbonized film 117, and crystal growth is performed while maintaining the non-contact state between the crucible 110 and the crystal ID _b. Thus, the generation of dislocations can be suppressed, and a crystal having excellent optical characteristics such as internal transmittance can be manufactured.

  FIG. 6 shows a schematic configuration of a crystal manufacturing apparatus 100A as a modification of the crystal manufacturing apparatus 100 shown in FIG. The crystal manufacturing apparatus 100A is the same in basic configuration as the crystal manufacturing apparatus 100, and common constituent elements are given the same reference numerals as in FIG. This modification differs from the crystal manufacturing apparatus 100 of FIG. 1 in that the material of the crucible 110A is an ultra-high bulk density carbon having a bulk density of 1.99 g / cc and an open porosity of 1%. The crystal manufacturing method using the crystal manufacturing apparatus 100A is the same as the method 1000 described above.

  As described above, according to the crystal manufacturing apparatuses 100 and 100A and the crystal manufacturing method 1000 of the present embodiment, generation and proliferation of dislocations in the growing crystal can be suppressed, and internal transmittance, laser durability, and the like can be suppressed. Crystals with excellent quality can be produced with good reproducibility.

  Then, the calcium fluoride single crystal obtained by the crystal manufacturing apparatuses 100 and 100A and the crystal manufacturing method 1000 is processed into a required optical element shape. Examples of optical elements include lenses, diffractive elements, optical film bodies, and composites thereof, such as lenses, multi-lenses, lens arrays, lenticular lenses, fly-eye lenses, aspheric lenses, diffraction gratings, binary optics elements, and the like. Of the complex.

  Further, the optical element includes an optical sensor (for example, an optical sensor for focus control) in addition to a single lens. Further, if necessary, an antireflection film may be provided on the surface of the optical element manufactured from the calcium fluoride single crystal. As the antireflection film, magnesium fluoride, aluminum oxide, and tantalum oxide are suitable, and these can be formed by vapor deposition by resistance heating, electron beam vapor deposition, sputtering, or the like.

  Since the optical element manufactured in this way is excellent in quality such as internal transmittance and laser durability, the optical performance is improved as compared with the conventional optical element.

If such an optical element is used, a projection optical system and an illumination optical system suitable for ArF excimer laser and F ₂ laser can be configured. An exposure apparatus for photolithography can be configured by combining various laser light sources, an optical system having the optical element, and a stage capable of moving the wafer.

  FIG. 7 shows an exposure apparatus 500 configured using optical elements manufactured from a calcium fluoride single crystal obtained from the crystal manufacturing apparatuses 100 and 100A and the crystal manufacturing method 1000.

  The exposure apparatus 500 includes an illumination apparatus 510 that illuminates a reticle 520 on which a circuit pattern is formed, a projection optical system 530 that projects diffracted light generated from the illuminated reticle pattern onto a plate 540, and a stage 545 that supports the plate 540. Have

  The exposure apparatus 500 is a projection exposure apparatus that exposes a plate 540 with a circuit pattern formed on the reticle 520 by, for example, a step-and-scan method or a step-and-repeat method. Such an exposure apparatus is suitable for a lithography process of submicron or quarter micron or less, and in the present embodiment, a step-and-scan type exposure apparatus (also referred to as “scanner”) will be described as an example.

  Here, the “step and scan method” means that the wafer is continuously scanned (scanned) with respect to the reticle to expose the reticle pattern onto the wafer, and the wafer is stepped after completion of one shot of exposure. The exposure method moves to the next exposure area. The “step-and-repeat method” is an exposure method in which the wafer is stepped and moved to the exposure area of the next shot for every batch exposure of the wafer.

  The illumination device 510 illuminates a reticle 520 on which a transfer circuit pattern is formed, and includes a light source unit 512 and an illumination optical system 514.

The light source unit 512 can use, for example, an ArF excimer laser with a wavelength of about 193 nm, a KrF excimer laser with a wavelength of about 248 nm, or the like as the light source. However, the type of the light source is not limited to the excimer laser. the _{F 2} laser or a YAG laser may be used. Further, the number of light sources is arbitrary. For example, if two solid-state lasers that operate independently are used, there is no mutual coherence between the solid-state lasers, and speckle due to the coherence is considerably reduced. Furthermore, in order to reduce speckles, the optical system may be swung linearly or rotationally. When a laser is used for the light source unit 512, a light beam shaping optical system that shapes a parallel light beam from the laser light source into a desired beam shape and an incoherent optical system that makes a coherent laser beam incoherent are used. Is preferred. A light source that can be used for the light source unit 512 is not limited to a laser, and one or a plurality of lamps such as a mercury lamp and a xenon lamp can be used.

  The illumination optical system 514 is an optical system that illuminates the reticle 520, and includes a lens, a mirror, an optical integrator, a stop, and the like. For example, a condenser lens, a fly-eye lens, an aperture stop, a condenser lens, a slit, and an imaging optical system are arranged in this order.

  The illumination optical system 514 can be used regardless of on-axis light or off-axis light. The optical integrator includes an integrator configured by stacking a fly-eye lens and two sets of cylindrical lens array (or lenticular lens) plates, and may be replaced by an optical rod or a diffractive element. An optical element manufactured from the calcium fluoride crystal of the present invention can be used as an optical element such as a lens of the illumination optical system 514.

  The reticle 520 is made of, for example, quartz, on which a circuit pattern (or image) to be transferred is formed, and is supported and driven by a reticle stage (not shown). Diffracted light emitted from the reticle 520 passes through the projection optical system 530 and is projected onto the plate 540. The reticle 520 and the plate 540 are optically conjugate. Since the exposure apparatus 500 of this embodiment is a scanner, the pattern of the reticle 520 is transferred onto the plate 540 by scanning the reticle 520 and the plate 540 at a speed ratio of the reduction magnification ratio. In the case of a step-and-repeat type exposure apparatus (also referred to as a “stepper”), exposure is performed with the reticle 520 and the plate 540 stationary.

  The projection optical system 530 is an optical system that projects light that reflects a pattern on the reticle 520 that is the object plane onto the plate 540 that is the image plane. The projection optical system 530 includes an optical system composed only of a plurality of lens elements, an optical system (catadioptric optical system) having a plurality of lens elements and at least one concave mirror, a plurality of lens elements, and at least one kinoform. An optical system having a diffractive optical element such as an all-mirror optical system can be used. When correction of chromatic aberration is required, a plurality of lens elements made of glass materials having different dispersion values (Abbe values) can be used, or the diffractive optical element can be configured to generate dispersion in the opposite direction to the lens element. To do. As the optical element such as a lens of the projection optical system 530, an optical element made of a calcium fluoride single crystal manufactured by the crystal manufacturing apparatuses 100 and 100A and the crystal manufacturing method 1000 of the first embodiment can be used. .

  The plate 540 is a wafer in this embodiment, but widely includes a liquid crystal substrate and other objects to be processed. The plate 540 is coated with a photoresist. The photoresist coating process includes a pretreatment, an adhesion improver coating process, a photoresist coating process, and a prebaking process. Pretreatment includes washing, drying and the like. The adhesion improver coating process is a surface modification process for improving the adhesion between the photoresist and the base (that is, a hydrophobic process by applying a surfactant), and an organic film such as HMDS (Hexamethyl-disilazane) is applied. Coat or steam. Pre-baking is a baking (baking) step, but is softer than that after development, and removes the solvent.

  The stage 545 supports the plate 540. Since any structure known in the art can be applied to the stage 545, detailed description of the structure and operation is omitted here. For example, the stage 545 can move the plate 540 in the XY directions using a linear motor. The reticle 520 and the plate 540 are synchronously scanned, for example, and the positions of the stage 545 and the reticle stage (not shown) are monitored by, for example, a laser interferometer, and both are driven at a constant speed ratio.

  The stage 545 is provided on a stage surface plate supported on a floor or the like via a damper, for example, and the reticle stage and the projection optical system 530 have a damper on a base frame placed on the floor or the like, for example. It is provided on a lens barrel surface plate (not shown) that is supported via the cable.

  In the exposure, the light beam emitted from the light source unit 514 illuminates the reticle 520 with the Koehler illumination, for example, by the illumination optical system 514. Light that passes through the reticle 520 and reflects the reticle pattern is imaged on the plate 540 by the projection optical system 530. The illumination optical system 514 and the projection optical system 530 used by the exposure apparatus 500 include an optical element manufactured from calcium fluoride according to the present invention, and transmit ultraviolet light, far ultraviolet light, and vacuum ultraviolet light with high transmittance. Therefore, it is possible to provide a device (semiconductor element, LCD element, imaging element (CCD, etc.), thin film magnetic head, etc.) with high throughput and high economic efficiency.

  Next, an embodiment of a device manufacturing method using the above-described exposure apparatus 500 will be described with reference to FIGS. FIG. 8 shows a flowchart for explaining the manufacture of devices (semiconductor chips such as IC and LSI, LCDs, CCDs, etc.). Here, the manufacture of a semiconductor chip will be described as an example.

  In step 1 (circuit design), a device circuit is designed. In step 2 (mask production), a mask on which the designed circuit pattern is formed is produced. In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by the lithography technique of the present invention using the mask and the wafer. Step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer created in step 4. The assembly process (dicing, bonding), packaging process (chip encapsulation), and the like are performed. Including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, the semiconductor device is completed and shipped (step 7).

  FIG. 9 is a detailed flowchart of the wafer process in Step 4. In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the surface of the wafer. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition or the like. Step 14 (ion implantation) implants ions into the wafer.

  In step 15 (resist process), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the exposure apparatus 500 to expose a circuit pattern on the mask onto the wafer. In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed.

  By repeatedly performing these steps, multiple circuit patterns are formed on the wafer.

  According to this device manufacturing method, it is possible to manufacture a higher quality device than before. Thus, the device manufacturing method using the exposure apparatus 500 and the resulting device also constitute one aspect of the present invention.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist. For example, the method of cooling the melted raw material may be any method other than the Bridgeman method, such as a method of pulling up the heater while fixing the crucible, a method of gradually decreasing the heater output, or the like.

Sectional drawing which shows schematic structure of the crystal manufacturing apparatus which is Example 1 of this invention. Schematic which shows the mode in the crucible during the crystal growth in the crystal manufacturing apparatus of Example 1. FIG. The figure which shows the crystallinity of the crystal manufactured with the conventional crystal manufacturing apparatus. FIG. 3 is a diagram showing the crystallinity of a crystal manufactured by the crystal manufacturing apparatus of Example 1. 3 is a flowchart for explaining the crystal manufacturing method according to the first embodiment. FIG. 3 is a schematic configuration diagram illustrating a crystal manufacturing apparatus that is a modification of the first embodiment. FIG. 5 is a block diagram showing a schematic configuration of an exposure apparatus that is Embodiment 2 of the present invention. 9 is a flowchart for explaining a device manufacturing method using the exposure apparatus according to the second embodiment. 9 is a detailed flowchart of the wafer process in Step 4 shown in FIG. 8.

Explanation of symbols

100,100A Crystal production apparatus 110,110A Crucible 117 Carbonized film 120 Support member 130 Crucible lifting / lowering part 140 Heater 160 Thermal insulation member 170 Housing 180 Melt upper space 182 Void between crucible and crystal ID Raw material SC Seed crystal CGF Growth furnace EM Exhaust device 500 Exposure device 510 Illumination device 514 Illumination optical system 530 Projection optical system

Claims (4)

A heater, a crucible disposed around the heater, and an elevating unit that moves the crucible relative to the heater; and a space in which the crucible is stored is evacuated and heated by the heater . and storing the calcium fluoride melt and cooling the calcium fluoride which is the molten by moving the crucible by the lifting unit in order to lower the temperature of the crucible, the crystal production for growing a single crystal of calcium fluoride A device,
In the crucible , the pressure in the space formed between the inner wall of the crucible and the single crystal is higher than the pressure in the space above the molten calcium fluoride and exhausted by the vacuum. as such, the gas permeability of the portion where the single crystal be formed a film of pyrolytic carbon or glassy carbon is inside some as follows ^{1 × 10 -4 cm 2 / s} , and wherein the crystalline Manufacturing equipment. The crystal manufacturing apparatus according to claim 1, wherein the crucible has the coating film formed on at least one of an outer surface and an inner surface thereof. The crucible is crystal manufacturing apparatus according to claim 1 or 2 its open pores are characterized in that, being formed of the film after having filled in the carbonized material. Comprising the steps of a space for accommodating the crucible was evacuated, so as to be arranged a heater around the crucible to melt the calcium fluoride which is accommodated in the crucible is heated by the heater,
Moving the crucible relative to the heater in order to lower the temperature of the crucible, comprising the steps of growing a single crystal of calcium fluoride, is cooled to the melting and calcium fluoride,
The crucible, the gas permeability of the portion where the single crystal be formed a film of pyrolytic carbon or glassy carbon is inside Yes in the following ^{1 × 10 -4 cm 2 / s} , the gas permeability Accordingly, the pressure in the space formed between the single crystal and the inner wall of the crucible is higher Ri by the pressure in the space is evacuated by the vacuum in the above Ri by calcium fluoride and the molten A crystal production method characterized by the above.