CN109423626B

CN109423626B - Film forming apparatus, film forming tray, film forming method, and method for manufacturing film forming tray

Info

Publication number: CN109423626B
Application number: CN201710764134.4A
Authority: CN
Inventors: 西山隆司; 中山孝
Original assignee: Sumco Corp
Current assignee: Sumco Corp
Priority date: 2017-08-30
Filing date: 2017-08-30
Publication date: 2021-07-09
Anticipated expiration: 2037-08-30
Also published as: CN109423626A

Abstract

The invention relates to a film forming apparatus, a film forming tray, a film forming method, and a method for manufacturing a film forming tray. The object is to reduce the manufacturing cost and improve the yield. A film forming apparatus, which carries silicon wafers (5) on a plurality of film forming trays (1) and conveys them on a film forming conveying path (11A), comprises a film forming heater (13B), a plurality of gas nozzles (13A, 13B, 13C) for blowing a raw material gas, and a circulating mechanism (15) for circulating the film forming trays after film forming; the film-forming tray consists of a tray main body (2) and a supporting ring (3) erected on the tray main body; the lower surface (3 d) of the mounting part (3 c) of the backup ring is separated from the surface (2 a) of the tray main body, the tray main body is made of powder sintered ceramics, and the backup ring is cut out from bulk ceramics grown from a gas phase.

Description

Film forming apparatus, film forming tray, film forming method, and method for manufacturing film forming tray

Technical Field

The present invention relates to a film forming apparatus, a film forming tray, a film forming method, and a method for manufacturing a film forming tray, and particularly to a technique suitably used for film formation by a CVD method using a CVD tray on which a silicon wafer is placed, and for film formation capable of uniformizing the thickness distribution of an oxide film formed on the surface of the silicon wafer.

Background

In the device process or the epitaxial silicon wafer manufacturing process, a process of forming a protective film and an insulating film on a silicon wafer is performed. For example, in the device process, an oxide film or the like is formed as an interlayer insulating film on the surface side of a silicon wafer used as a device fabrication region, and then wiring is formed.

In addition, in the process of manufacturing an epitaxial wafer, when a silicon epitaxial layer having a high resistivity is vapor-grown on the main surface of a silicon single crystal substrate having a low resistivity, a phenomenon in which a dopant in the silicon single crystal substrate is temporarily released into a vapor phase from the back surface of the silicon single crystal substrate or the like and is doped into the silicon epitaxial layer, so-called autodoping, is likely to occur. Therefore, before the vapor phase growth, the following processes are performed: a silicon oxide film is formed on the back surface side of a silicon single crystal substrate on which an epitaxial layer is not formed as a protective film for preventing autodoping.

In general, when an oxide film is formed as an insulating film or a protective film on a silicon wafer, an atmospheric pressure CVD method is used. In the atmospheric pressure CVD method, after a silicon wafer is placed on a tray with the side of a film formation surface as an upper side, a component corresponding to a source gas is deposited on the silicon wafer to form a film by heating the tray and the silicon wafer while supplying the source gas onto the silicon wafer. The atmospheric pressure CVD method is widely used for forming an oxide film because the film forming speed is high, so that the time required for forming the oxide film can be shortened, and the oxide film can be continuously formed on a silicon wafer by mounting the apparatus on a conveyor.

In such an atmospheric pressure CVD method, monosilane (SiH) is used as a raw material gas₄) With oxygen (O)₂) Or tetraethoxysilane (TEOS, chemical formula: si (OC)₂H₅）₄) With ozone (O)₃) The mixed gas of (1).

The tray on which the silicon wafer is placed when the oxide film is formed by the atmospheric pressure CVD method requires the following characteristics: not deformed by heating during film formation and not causing contamination of the silicon wafer. Therefore, the tray is made of a sintered SiC material, or has a structure in which the surface thereof is further coated with a SiC film. As a general tray shape, a flat shape of a placing part for supporting a silicon wafer is used.

FIG. 34 is a cross-sectional view showing a state where a conventional placing section places a silicon wafer on a flat tray. The tray 1 shown in fig. 34 has a flat placement portion 1a on which the silicon wafer 5 is placed. When the silicon wafer 5 is placed on the tray 1, if the film is formed on the film formation surface 5a of the silicon wafer by the normal pressure CVD method using the tray shown in fig. 10, the non-film formation surface 5c of the silicon wafer on which the film is not formed comes into contact with the placement portion 1a of the tray, and therefore, the entire surface of the non-film formation surface 5c of the silicon wafer is damaged. The depth of the contact flaw is slightly different depending on the film forming conditions, but the contact flaw having a depth of about 3 to 10 μm is generated.

When the formed oxide film is used as an interlayer insulating film, if a rapid thermal history is applied to a silicon wafer by a heat treatment such as Flash-Lamp-Anneal (Flash-Lamp-Anneal) in a device process, the silicon wafer may be cracked from the contact damage, which may deteriorate the yield of the product. In addition, in the case of using an oxide film as a protective film, if an epitaxial layer is formed on the surface of a silicon wafer where a contact damage has occurred, there is a problem that a stacking fault or the like occurs in the epitaxial layer from the contact damage as a starting point. In order to solve the problem of occurrence of contact damage on a silicon wafer during film formation by the atmospheric pressure CVD method, patent document 1 uses a tray for supporting the outer peripheral portion of the silicon wafer.

Fig. 35 is a cross-sectional view showing a state where a silicon wafer is mounted on a conventional tray for supporting the outer peripheral portion of the silicon wafer. The tray 1 shown in fig. 35 has a tapered placement portion 1a, and the placement portion 1a supports the outer peripheral portion 5b of the silicon wafer and places the silicon wafer 5 on the tray 1.

When a tray for supporting the outer peripheral portion of the silicon wafer is used, the silicon wafer is supported in a state where the non-film formation surface 5c of the silicon wafer is not in contact with the tray 1, so that the occurrence of contact damage can be greatly reduced.

However, according to the experiments of the present inventors, when a tray supporting the outer peripheral portion of the silicon wafer is used, if heating is performed at the time of film formation by the atmospheric pressure CVD method, the surface temperature near the outer peripheral portion of the silicon wafer rises due to heat conduction from the tray 1 to the outer peripheral portion 5b of the silicon wafer, the temperature distribution in the film formation surface 5a of the silicon wafer is dispersed, and the film thickness of the oxide film to be formed is not uniform. Specifically, since the increase in the surface temperature increases the growth rate of the oxide film, the oxide film formed on the film formation surface 5a of the silicon wafer becomes thinner at the center and thicker near the outer peripheral portion.

Therefore, in a device process using a formed oxide film as an interlayer insulating film, when a silicon wafer having an uneven oxide film thickness is used, there is a problem that device characteristics formed on the oxide film are significantly degraded.

Further, in recent years, there has been a demand for providing an epitaxial silicon wafer having a high flatness, and in the case where the oxide film thickness of the silicon wafer used is not uniform, there has been a problem that the flatness of the epitaxial wafer formed thereafter is deteriorated.

Further, if there is a damage on the surface of the silicon wafer on which the epitaxial layer is formed as described above, there is a possibility that a defect may occur in the formed epitaxial layer. Therefore, after the oxide film is formed and before the epitaxial growth process, an operation of polishing one side of the non-film-formed surface to remove the oxide film, the damage, and the like is performed.

However, since the single-side polishing process is performed with the film formation surface held and the non-film formation surface side subjected to single-side polishing, if the oxide film thickness distribution is not uniform, the wafer is held while being elastically deformed, and the non-uniform oxide film thickness distribution is transferred to the non-film formation surface after polishing, so that the flatness of the silicon wafer is deteriorated. The greater the polishing amount, the greater the degree of deterioration of the flatness, and the greater the flatness of the epitaxial wafer to be formed.

Patent document 1: japanese patent laid-open No. 11-329983.

Patent document 2: japanese patent re-publication No. 2011/070741.

Disclosure of Invention

As described above, in the conventional tray used for forming an oxide film by the atmospheric pressure CVD method, there are problems that a contact flaw is generated on a non-film formation surface of a silicon wafer and a thickness distribution of the oxide film formed on the silicon wafer becomes uneven.

The present inventors have made special studies to solve the problem, and as shown in patent document 2, have found a technique of supporting a silicon wafer only by a peripheral edge and separating the silicon wafer from a tray.

However, in patent document 2, it is known that if the thickness of the support member 3 for supporting the silicon wafer only with the peripheral edge is large, the variation in the temperature distribution of the silicon wafer cannot be improved.

If the thickness of the support member 3 is reduced in order to improve the dispersion of the temperature distribution, it is newly found that cracking occurs and the production yield of the support member 3 is excessively deteriorated in the case of production by a conventional production method such as sintering SiC or coating the surface with a SiC film.

Further, since the support member 3 supports the silicon wafer only by the peripheral edge, the stress is large, and a problem that cracking may occur in the film forming process is newly found.

The present invention has been made in view of such circumstances, and an object thereof is to provide the following technology: when the method is used for film formation by an atmospheric pressure CVD method, the thickness distribution of an oxide film formed on a silicon wafer can be made more uniform without generating contact damage on a non-film formation surface of the silicon wafer, and the yield in manufacturing a film formation tray can be improved, thereby reducing the manufacturing cost.

The film forming apparatus of the present invention includes: a plurality of film forming trays on which silicon wafers are mounted; a film forming tray driving mechanism that continuously conveys the film forming tray on a film forming conveyance path extending in a horizontal direction along a main surface of the film forming tray; a plurality of gas nozzles for blowing a source gas toward the silicon wafer; a film-forming heater for heating the film-forming tray; a loading/unloading mechanism for delivering and receiving the silicon wafer to and from the film formation tray at a loading/unloading position; a circulating mechanism for circulating the film-forming tray after film formation to the loading/unloading position along a circulating conveying path; the film forming tray comprises a tray main body and a support ring which is erected on the tray main body and supports the outer circumference position of the silicon wafer, and a carrying part for directly carrying the silicon wafer is arranged on the support ring; the placing part has a lower surface of the placing part, which is separated from the surface of the tray main body opposite to the silicon wafer placed at a distance; the tray main body is made of powder sintered ceramics, and the backup ring is cut out from a large block of ceramics grown in a vapor phase; thereby, the above-described problems are solved.

In the film forming apparatus of the present invention, the film forming heater may be provided at a position below the film forming conveyance path, and the film forming tray may be heated from a lower surface side thereof.

In the film deposition apparatus of the present invention, the gas shower head may be provided at an upper position of the film deposition transport path.

The film forming apparatus of the present invention may be configured such that the loading/unloading mechanism includes support pins capable of supporting the silicon wafer in a state of penetrating the film forming tray and being driven in a vertical direction when the silicon wafer is transferred to and from the film forming tray; the film forming tray is provided with a pin through hole through which the support pin can pass.

In the film deposition apparatus of the present invention, the silicon wafer may have a substantially circular outline.

In the film forming apparatus of the present invention, the source gas supplied to the showerhead may include at least a silicon-containing gas and an oxygen-containing gas.

The film forming tray of the present invention is continuously conveyed in a film forming conveyance path, and is used in a film forming apparatus for forming a film on a silicon wafer mounted thereon by blowing a raw material gas from a plurality of gas nozzles, and may be composed of a tray main body and a support ring which is erected on the tray main body and supports the silicon wafer, wherein the support ring is provided with a placement portion for directly placing an outer peripheral position of the silicon wafer; the placing part has a lower surface of the placing part, which is separated from the surface of the tray main body opposite to the silicon wafer placed at a distance; the tray main body is made of powder sintered ceramics, and the backup ring is cut out from a bulk ceramic grown from a vapor phase.

The film forming tray of the present invention may have a plate shape in which the outline of the tray main body is rectangular in a plan view.

The film formation tray of the present invention may be configured such that the tray body is provided with a pin through-hole so that the support pin capable of supporting the silicon wafer can be driven in the vertical direction when the silicon wafer is transferred.

In the film formation tray of the present invention, a recessed receiving portion that receives the support ring having a circular shape in plan view in accordance with a planar contour of the silicon wafer may be formed on an upper surface of the tray main body.

In the film formation tray of the present invention, a drive concave portion for receiving a driving force from a film formation tray driving mechanism as a state in which a plurality of sheets are continuously arranged when the sheet is conveyed in the film formation conveying path may be provided on a lower surface of the tray main body.

The film forming tray of the present invention may be configured such that the thickness of the tray body is set to be in the range of 5 to 10 mm.

The support ring of the film forming tray of the present invention may be such that the arithmetic mean roughness Ra of the surface of the placing part on which the silicon wafer is placed is set to be in the range of 0.01 to 2.0 μm.

The supporting ring of the film forming tray of the present invention may have a ratio of a heat capacity to an inner diameter of the supporting ring (heat capacity/inner diameter) set in a range of 1.2 to 5.5 (J/K)/cm.

The support ring of the film forming tray of the present invention may have a ratio of an outer diameter to an inner diameter of the mounting portion (outer diameter/inner diameter) set in a range of 1.02 to 1.10.

The support ring of the film forming tray of the present invention may have a thickness dimension from the lower surface to the uppermost surface of the mounting portion in a range of 0.4 to 1.10 mm.

The support ring of the film forming tray of the present invention may have a height dimension from the upper surface of the mounting portion to the uppermost surface of the mounting portion in a range of 0.2 to 0.6 mm.

The method for manufacturing a film formation tray of the present invention is any one of the above methods for manufacturing a film formation tray, and may include a step of forming the tray body into a ceramic sintered body formed of a sintered powder, and a step of vapor-phase growing a ceramic film on a surface of the sintered body.

The method of manufacturing a film formation tray according to the present invention is any one of the above methods, and may include a step of vapor-phase growing a bulk ceramic on a predetermined substrate by the backup ring, and a cutting step of cutting a predetermined portion from the bulk ceramic to form the mount portion.

The method for forming a film of the present invention can form an oxide film on the entire surface of the silicon wafer by the film forming apparatus described in any of the above.

The present inventors have conducted various experiments to solve the above-described problems and have conducted extensive studies, and as a result, have found that a tray comprising a tray main body and a support ring which is erected on the tray main body and supports a silicon wafer, a placement portion on which the silicon wafer is directly placed being provided on the support ring, and the placement portion having a placement portion lower surface which is separated from the tray main body, can make the thickness distribution of an oxide film formed on the silicon wafer uniform.

Further, it is recognized that the placing portion is formed by the inclined surface, the inner circumferential side of the placing portion is arranged to be close to the surface of the tray main body facing the placed silicon wafer at a distance, and the outer circumferential portion of the silicon wafer is supported by the placing portion, whereby the thickness distribution of the oxide film formed on the silicon wafer can be made uniform without causing contact damage to the silicon wafer.

Further, it has been found that the thickness distribution of the oxide film formed on the silicon wafer can be made more uniform by making the tray have a structure in which the contact area between the backup ring and the tray main body is reduced.

Further, the present invention has been completed based on the knowledge that the present invention has been made in detail also in a film forming tray, a method for manufacturing the film forming tray, a film forming apparatus, and a film forming method.

The film forming apparatus of the present invention may include: a plurality of film forming trays on which silicon wafers are mounted; a film forming tray driving mechanism that continuously conveys the film forming tray on a film forming conveyance path extending in a horizontal direction along a main surface of the film forming tray; a plurality of gas nozzles for blowing a source gas toward the silicon wafer; a film-forming heater for heating the film-forming tray; a loading/unloading mechanism for delivering and receiving the silicon wafer to and from the film formation tray at a loading/unloading position; a circulating mechanism for circulating the film-forming tray after film formation to the loading/unloading position along a circulating conveying path; the film forming tray comprises a tray main body and a support ring which is erected on the tray main body and supports the outer circumference position of the silicon wafer, and a carrying part for directly carrying the silicon wafer is arranged on the support ring; the placing part has a lower surface of the placing part, which is separated from the surface of the tray main body opposite to the silicon wafer placed at a distance; the tray main body is made of powder sintered ceramics, and the backup ring is cut out from a large block of ceramics grown in a vapor phase; thus, for example, the tray body and the backup ring made of SiC ceramics can have strength capable of supporting a silicon wafer, prevent the backup ring from cracking, improve the yield of manufacturing the backup ring, ensure uniformity of the temperature state of the silicon wafer, and improve uniformity of film formation sequentially performed on a plurality of silicon wafers.

Further, in the present invention, by providing a preheating heater for heating the silicon wafer before film formation, the temperature distribution of the silicon wafer before film formation can be made uniform, and the film formation characteristics can be improved.

In the film forming apparatus of the present invention, the film forming heater is provided at a position below the film forming conveyance path, and the film forming tray is heated from the lower surface side thereof, whereby the temperature distribution of the silicon wafer when heated by the film forming tray heated from the lower surface can be made uniform, and the film forming characteristics can be improved.

In the film deposition apparatus of the present invention, the gas showerhead is provided at a position above the film deposition transport path, so that a raw material gas (film deposition gas) can be ejected from the gas showerhead toward the upper film deposition surface of the heated silicon wafer, and film deposition can be performed while the film deposition temperature on the film deposition surface of the silicon wafer is set within a predetermined range.

In the present invention, the gas showerhead has an opening (slot nozzle) extending in a direction (lateral direction) orthogonal to the moving direction of the film formation tray, and can discharge the source gas over the entire length in the lateral direction of the moving silicon wafer. Further, a plurality of such opening portions (slit nozzles) extending in a direction (lateral direction) orthogonal to the moving direction of the film formation tray may be provided in parallel in the moving direction (longitudinal direction) of the film formation tray.

The film forming apparatus of the present invention is characterized in that the loading/unloading mechanism includes a support pin capable of supporting the silicon wafer in a state of penetrating the film forming tray and being driven in a vertical direction when the silicon wafer is transferred to/from the film forming tray; the film formation tray is provided with pin through holes through which the support pins can penetrate, and thus, the silicon wafer can be smoothly transferred to and from the film formation tray without affecting the temperature state of the silicon wafer during film formation. At the same time, for example, when an oxide film for gettering is formed on a silicon wafer, it is possible to prevent the occurrence of damage such as a flaw on the surface (back surface) opposite to the silicon wafer processing surface of the film forming apparatus, which is the device forming surface, and to prevent a decrease in the yield of the silicon wafer.

The film forming apparatus of the present invention can continuously form an entire oxide film on a plurality of silicon wafers having a diameter of, for example, about 300mm by forming the silicon wafers into a substantially circular outline.

The material gas supplied to the showerhead of the film forming apparatus of the present invention includes at least a gas containing silicon (Si) and a gas containing oxygen (O), and thus can be suitably used for forming an oxide film for gettering on a silicon wafer.

The film forming tray of the present invention is continuously conveyed in a film forming conveying path, and is used in a film forming apparatus for forming a film on a silicon wafer mounted thereon by blowing a raw material gas from a plurality of gas nozzles, and may be composed of a tray main body and a support ring which is erected on the tray main body and supports the silicon wafer, wherein a mounting portion for directly mounting an outer peripheral position of the silicon wafer is provided on the support ring; the placing part has a lower surface of the placing part, which is separated from the surface of the tray main body opposite to the silicon wafer placed at a distance; further, since the tray main body is made of powder sintered ceramic and the backup ring is cut out from bulk ceramic grown in a vapor phase, for example, the tray main body and the backup ring made of SiC ceramic can have strength capable of supporting a silicon wafer, prevent the backup ring from cracking, improve the yield of manufacturing the backup ring, ensure uniformity of the temperature state of the silicon wafer, and improve the in-plane uniformity of film formation on the mounted silicon wafer.

In the film formation tray of the present invention, the outline of the tray main body is formed in a rectangular plate shape in a plan view, and thus the long sides of the tray outline extend in the direction (lateral direction) orthogonal to the moving direction of the film formation tray, and the short sides extend in the moving direction (longitudinal direction) of the film formation tray, and further, the film formation tray can be heated in a state where a plurality of trays are in close proximity to each other. This improves the heating efficiency by the film formation heater, improves the uniformity of the temperature state in the silicon wafer plane in the moving direction (longitudinal direction), and improves the uniformity of the temperature state of the plurality of silicon wafers, thereby improving the film formation characteristics.

Further, the gas showerhead has an opening (nozzle) extending in a direction (lateral direction) orthogonal to the moving direction of the film formation tray, and when the raw material gas is ejected over the entire lateral length of the moving silicon wafer, unnecessary film formation between the film formation trays can be reduced, generation of particles in the apparatus can be reduced, and adverse effects on film formation can be reduced.

The film formation tray of the present invention is provided with a pin through hole penetrating the tray main body, so that the support pin capable of supporting the silicon wafer can be driven in the vertical direction when the silicon wafer is delivered, and thus the silicon wafer can be delivered smoothly to the film formation tray without affecting the temperature state of the silicon wafer at the time of film formation. At the same time, for example, when an oxide film for gettering is formed on a silicon wafer, it is possible to prevent the occurrence of damage such as a flaw on the surface (back surface) opposite to the silicon wafer processing surface of the film forming apparatus, which is the device forming surface, and to prevent a decrease in the yield of the silicon wafer.

In the film formation tray of the present invention, the upper surface of the tray main body is formed with a concave receiving portion for receiving the backup ring formed in a circular shape in plan view in accordance with the plan contour of the silicon wafer, whereby the upper surface of the tray main body, the uppermost surface of the backup ring, and the film formation surface of the silicon wafer are substantially flush with each other, and it is possible to prevent unnecessary turbulence of a gas flow from occurring in a film formation gas (raw material gas) during film formation. Further, since the backup ring and the silicon wafer can be stably held by the tray main body, it is possible to prevent positional variations of the backup ring and the silicon wafer with respect to the tray main body moving in the film formation conveyance path, and to maintain the position of the silicon wafer with respect to the gas ejection head at a predetermined state during film formation, thereby improving film formation characteristics of the silicon wafer.

In the film formation tray of the present invention, a drive concave portion for receiving a drive force from a film formation tray drive mechanism as a state in which a plurality of sheets are continuously arranged when the film formation tray is conveyed in the film formation conveyance path is provided on a lower surface of the tray main body, and thereby the film formation tray can be driven in the following states: the lower surface of the tray main body, which is heated by being placed opposite to the film-forming heater, is provided with a portion, which is not blocked by the film-forming heater, except for the driving recess portion, as small as possible. Thus, the tray main body can be moved in a stable state in the film formation conveyance path, and since there are few places other than the drive recess where the tray main body abuts, the occurrence of unevenness in the heating state of the silicon wafer heated via the tray main body can be reduced. This can achieve stability of film formation.

The film forming tray of the present invention is configured such that the thickness dimension of the tray main body is set within a range of 5 to 10mm, thereby achieving a sufficient temperature rise with respect to heating by a film forming heater, maintaining uniformity with respect to the temperature rise of a wafer, and having sufficient strength with respect to support and conveyance of a silicon wafer and a support ring.

The support ring of the film forming tray of the present invention sets the arithmetic mean roughness Ra of the surface of the mounting part on which the silicon wafer is mounted to be in the range of 0.01 to 2.0 μm, thereby eliminating the possibility that the silicon wafer is bonded to the mounting part when the surface roughness Ra is smaller than the range, and preventing the occurrence of a gap between the silicon wafer and the mounting part to reduce the sealing degree and prevent the raw material gas from bypassing from the gap into the space (the back surface side of the silicon wafer) between the silicon wafer and the tray main body when the surface roughness Ra is larger than the range.

The supporting ring of the film forming tray of the present invention has a ratio of heat capacity to inner diameter of the supporting ring (heat capacity/inner diameter) set in a range of 1.2 to 5.5 (J/K)/cm, thereby avoiding the following problems. Here, the ratio (heat capacity/inner diameter) represents the efficiency of the heat capacity of the backup ring with respect to the silicon wafer.

The problem is that: if the ratio of the heat capacity of the backup ring placement unit to the silicon wafer is larger than the above range, the temperature of the silicon wafer may decrease when the raw material gas is introduced, and in this case, the temperature of the backup ring placement unit does not follow the decrease, and as a result, the temperature of the outer peripheral portion of the silicon wafer becomes higher than that of the central portion, and the in-plane uniformity of the film deposition may deteriorate, which is not preferable. Further, if the ratio of the heat capacities is less than the above range, the volume of the backup ring becomes too small, so that the strength cannot be maintained and the backup ring is difficult to manufacture, and the temperature distribution in the tray main body reflecting the temperature distribution of the film formation heater also affects the temperature distribution of the backup ring mounting portion, so that the in-plane uniformity of the film formation may be deteriorated, which is not preferable.

The supporting ring of the film forming tray of the present invention has a ratio (outer diameter/inner diameter) of the outer diameter to the inner diameter of the mounting portion in a range of 1.02 to 1.10, thereby avoiding the following problems. The problem is that: if the ratio of the outer diameter to the inner diameter, that is, the width dimension of the backup ring, is made smaller, the tray main body comes too close to the outer periphery of the silicon wafer, and therefore the influence of the heat transfer plus the radiant heat becomes larger, and the temperature of the outer periphery of the silicon wafer may become higher, which is not preferable. Further, if the width dimension of the backup ring, which is the ratio of the outer diameter to the inner diameter, is too large, it is necessary to make the backup ring thin in order to reduce the heat capacity, the rigidity is insufficient to deform the backup ring, or the volume of the backup ring becomes too small, so that the strength cannot be maintained and the manufacturing of the backup ring becomes difficult, which is not preferable.

The support ring of the film forming tray of the present invention has a thickness dimension from the lower surface to the uppermost surface of the mounting portion in the range of 0.4 to 1.10mm, so that the heat capacity and the width dimension of the support ring can be set in the above ranges, and the following problems do not occur. The problem is that: if the heat capacity of the backup ring placement unit is too large, the temperature of the silicon wafer may decrease when the source gas is introduced, and in this case, the temperature of the backup ring placement unit does not follow the decrease, and as a result, the temperature of the outer peripheral portion of the silicon wafer becomes higher than that of the central portion, and the in-plane uniformity of the film deposition may deteriorate, which is not preferable. Further, if the heat capacity of the backup ring is too small, the volume of the backup ring becomes too small, so that the strength cannot be maintained and the backup ring is difficult to manufacture, and the temperature distribution in the tray main body reflecting the temperature distribution of the film formation heater also affects the temperature distribution of the backup ring mounting portion, so that the in-plane uniformity of the film formation may be deteriorated, which is not preferable. Further, if the width of the backup ring is too small, the tray main body comes too close to the outer periphery of the silicon wafer, and therefore, the influence of the radiation heat is large in addition to the influence of the conduction heat, and the temperature of the outer periphery of the silicon wafer may become too high, which is not preferable. Further, if the width dimension of the backup ring is too large, it is necessary to make the backup ring thin in order to reduce the heat capacity, and the backup ring is deformed due to insufficient rigidity, or the volume of the backup ring becomes too small, so that it is not possible to maintain the strength and the manufacturing of the backup ring becomes difficult, which is not preferable.

In the film formation tray of the present invention, the support ring is set such that the height from the upper surface of the mounting portion to the uppermost surface is in the range of 0.2 to 0.6mm, and thus the height, that is, the depth of the mounting portion can be set to be equal to or less than the thickness of the silicon wafer, and thus the silicon wafer can be set to a position higher than the uppermost surface of the support ring and the uppermost surface of the tray body, so that the raw material gas ejected onto the silicon wafer flows toward the periphery and further from the uppermost surface of the support ring to the uppermost surface of the tray body, and no disturbance occurs in the gas flow. On the other hand, when the depth of the placing part is not less than the thickness of the silicon wafer, the raw material gas collides with the side wall of the support ring placing part to generate turbulence, and the thickness of the outer periphery of the silicon wafer may be uneven. When the height, i.e., the depth of the placing part, is smaller than the above range, the raw material gas may bypass to the silicon wafer bevel part side, which is the back side of the silicon wafer outer peripheral part, and the placing part and the silicon wafer may be easily bonded to each other, which is not preferable.

The method for manufacturing a film formation tray according to the present invention is a method for manufacturing a film formation tray according to any one of the above, including a step of forming the tray body into a ceramic sintered body formed of a sintered powder, and a step of vapor-phase growing a ceramic film on the surface of the sintered body, and thereby, for example, by depositing a film of SiC by CVD on the surface of the sintered body formed by sintering a powder of silicon-impregnated SiC, the conditions of the heat capacity, strength, and the like can be satisfied at low cost.

The method of manufacturing a film formation tray according to the present invention is the method of manufacturing a film formation tray according to any one of the above-described methods, including the step of vapor-phase growing a bulk ceramic on a predetermined substrate by the backup ring, and the step of cutting out a predetermined portion from the bulk ceramic to form the mount portion, thus, a film of, for example, SiC is deposited by CVD (chemical vapor deposition) on a substrate for producing a bearing ring to form a bulk state, a bearing ring is formed by cutting out from the bulk, thereby, a high-purity, high-density and high-strength backup ring can be manufactured, the strength for stably supporting the silicon wafer, the state of no crack and the surface roughness of the part contacting with the silicon wafer can be maintained in a predetermined range, in addition, in the manufacturing process, the yield of the manufacturing of the backup ring is improved and the manufacturing cost is reduced, wherein the occurrence of breakage is reduced when the placing part is cut out.

In the film formation method of the present invention, the entire oxide film of the silicon wafer is formed by the film formation apparatus described in any one of the above, whereby a silicon wafer having excellent surface characteristics, getter characteristics, and the like, which is suitable for device manufacturing and the like, can be manufactured.

In the present invention, the film formation tray may be made of a ceramic material, such as SiC (silicon carbide).

The present invention has been completed based on the above-described findings, and may be the following trays for film formation (1) to (9) and the following film formation method (10).

(1) A film forming tray (CVD tray) used for film forming by CVD method, comprising a tray main body and a support ring mounted on the tray main body and supporting a silicon wafer, characterized in that the support ring is provided with a placing part for directly placing the silicon wafer; the placing part has a lower surface of the placing part, and the lower surface of the placing part is separated from the surface of the tray main body opposite to the silicon wafer placed at a distance.

(2) The film forming tray according to the above (1), characterized by having a structure in which a contact area between the backup ring and the tray main body is reduced.

(3) The film forming tray according to the above (2), wherein a protruding portion is provided on the tray main body and the support ring is bridged on the protruding portion as a structure for reducing the contact area.

(4) The film forming tray according to the above (2), wherein the support ring is provided so as to be bridged on the tray main body via point contact or line contact as a structure for reducing the contact area.

(5) The film forming tray according to (2) above, further comprising a jig for supporting the backup ring, wherein the backup ring is mounted on the tray main body via point contact or line contact by the jig as a structure for reducing the contact area.

(6) The film forming tray according to the above (3), wherein the tray main body has a recessed receiving portion for receiving the backup ring, and an inner peripheral surface of the receiving portion is formed as an inclined surface, and an upper portion of the inclined surface is disposed away from a center of the receiving portion.

(7) The film formation tray according to any one of the above (1) to (6), wherein the placement portion is formed by an inclined surface, and is disposed so that an inner circumferential side thereof is close to a surface of the tray main body facing the silicon wafer placed thereon at a distance, and supports an outer circumferential portion of the silicon wafer.

(8) The film forming tray according to any one of the above (1) to (7), wherein the mounting portion is annular.

(9) The film formation tray according to any one of the above (1) to (8), wherein the mount portion is made of SiC.

(10) A film forming method comprising placing a silicon wafer on a film forming tray, supplying a source gas to the silicon wafer, heating the silicon wafer, and forming a film on the silicon wafer by a CVD method, wherein the film forming tray according to any one of the above (1) to (9) is used as the tray.

According to the present invention, the following effects can be achieved: the backup ring can follow the temperature change of the silicon wafer during the heating by the film forming heater and the temperature drop caused by the heating stop, and has sufficient strength, thereby preventing the adhesion of the field of the in-plane temperature distribution of the silicon wafer, improving the film forming property relative to the silicon wafer, improving the yield in the manufacturing of the film forming tray, and providing a lot of the silicon wafers at low cost.

Further, when the film is used for film formation on a silicon wafer by an atmospheric pressure CVD method, the thickness distribution of the oxide film to be formed can be made uniform without causing contact damage to the non-film formation surface of the silicon wafer.

Further, since the heat conduction from the tray body to the backup ring is reduced by making the film formation tray have a structure in which the contact area between the backup ring and the tray body is reduced, the heat conduction from the mount portion to the outer peripheral portion of the silicon wafer can be further reduced, and the thickness distribution of the oxide film to be formed can be made more uniform.

Drawings

Fig. 1 is a schematic view showing a film deposition apparatus according to embodiment 1 of the present invention.

Fig. 2 is a plan view showing embodiment 1 of the film forming tray according to the present invention.

Fig. 3 is a front cross-sectional view showing embodiment 1 of a film forming tray according to the present invention.

Fig. 4 is a plan view showing a backup ring according to embodiment 1 of the film forming tray of the present invention.

Fig. 5 is a cross-sectional view showing a backup ring according to embodiment 1 of the film forming tray of the present invention.

Fig. 6 is a plan view showing a tray main body according to embodiment 1 of the film forming tray of the present invention.

Fig. 7 is a cross-sectional view showing a tray main body according to embodiment 1 of the film forming tray of the present invention.

Fig. 8 is a sectional view showing a process for manufacturing a backup ring according to embodiment 1 of the film forming tray of the present invention.

Fig. 9 is a sectional view showing a process for manufacturing a backup ring according to embodiment 1 of the film forming tray of the present invention.

Fig. 10 is a process diagram showing a manufacturing process of a tray main body according to embodiment 1 of the film forming tray of the present invention.

Fig. 11 is a process diagram showing a manufacturing process of a tray main body according to embodiment 1 of the film forming tray of the present invention.

Fig. 12 is a process diagram showing a manufacturing process of a tray main body according to embodiment 1 of the film forming tray of the present invention.

Fig. 13 is a process diagram showing a manufacturing process of a tray main body according to embodiment 1 of the film forming tray of the present invention.

Fig. 14 is a process diagram showing a manufacturing process of a tray main body according to embodiment 1 of the film forming tray of the present invention.

Fig. 15 is a process diagram showing a manufacturing process of a tray main body according to embodiment 1 of the film forming tray of the present invention.

Fig. 16 is a front cross-sectional view showing a case where the tray main body of embodiment 2 of the film formation tray according to the present invention has a receiving portion.

Fig. 17 is a front cross-sectional view showing a case where a planar tray main body is used and a backup ring is supported on the outer periphery of the tray according to embodiment 2 of the present invention.

Fig. 18 is a front cross-sectional view showing a case where a planar tray main body is used and a backup ring is supported by an intermediate portion according to embodiment 2 of the film forming tray of the present invention.

Fig. 19 is a front cross-sectional view showing a case where a concave portion is provided on a surface of a tray main body facing a silicon wafer according to embodiment 2 of the present invention.

Fig. 20 is a plan view showing a case where a projection is provided on a tray main body according to embodiment 3 of the film forming tray of the present invention.

Fig. 21 is a cross-sectional view showing embodiment 3 of a film forming tray according to the present invention.

Fig. 22 is a cross-sectional view showing a case where a planar tray main body is used according to embodiment 4 of the film formation tray of the present invention.

Fig. 23 is a cross-sectional view showing a case where the tray main body of embodiment 4 of the film formation tray according to the present invention has a receiving portion.

Fig. 24 is a cross-sectional view showing a case where a concave portion is provided below a mounting portion according to embodiment 4 of the film formation tray of the present invention.

Fig. 25 is a plan view showing a case where a backup ring is bridged via point contact and line contact in embodiment 5 of the film forming tray according to the present invention.

Fig. 26 is a cross-sectional view showing embodiment 5 of a film forming tray according to the present invention.

Fig. 27 is a cross-sectional view showing a case where a backup ring is bridged via linear contact on a tray main body having a concave receiving portion according to embodiment 6 of the film forming tray of the present invention.

Fig. 28 is a cross-sectional view showing a case where a support ring is bridged via linear contact on a planar tray main body according to embodiment 6 of the film forming tray of the present invention.

Fig. 29 is a cross-sectional view showing a case where a backup ring is bridged via point contact with a jig according to embodiment 7 of the film forming tray of the present invention.

Fig. 30 is a cross-sectional view showing a case where a backup ring is bridged via line contact with a jig according to embodiment 7 of the film forming tray of the present invention.

Fig. 31 is a view showing the thickness distribution of an oxide film when the film is formed on a silicon wafer using the film formation tray of the present invention.

Fig. 32 is a view showing the thickness distribution of an oxide film when a film is formed on a silicon wafer using a conventional tray for supporting the outer peripheral portion of the silicon wafer.

Fig. 33 is a diagram showing a thickness distribution of an oxide film formed when a film is formed by a CVD method using a tray having a structure in which a contact area is reduced or a tray having no structure.

FIG. 34 is a cross-sectional view showing a state where a conventional placing section places a silicon wafer on a flat tray.

Fig. 35 is a cross-sectional view showing a state where a silicon wafer is mounted on a conventional tray for supporting the outer peripheral portion of the silicon wafer.

Detailed Description

Hereinafter, a film deposition apparatus, a film deposition tray, a film deposition method, and a method for manufacturing a film deposition tray according to embodiment 1 of the present invention will be described with reference to the drawings.

Fig. 1 is a perspective view showing a film deposition apparatus according to the present embodiment, and reference numeral 10 in the drawing denotes a film deposition apparatus.

The film formation apparatus 10 according to the present embodiment is an apparatus for forming an oxide film on the entire surface of the silicon wafer 5 having a substantially circular outline, for example. The film formation apparatus 10 of the present embodiment is not limited to this processing application, but can be used for manufacturing a silicon wafer to be supplied to a device manufacturing process.

As shown in fig. 1, the film deposition apparatus 10 according to the present embodiment includes a plurality of

film deposition trays

1 and 1 on which silicon wafers 5 are mounted, a film deposition tray driving mechanism 11 that continuously conveys the film deposition trays 1 along a film deposition conveyance path 11A extending in a horizontal direction along main surfaces thereof, a preheating heater 12a that heats the silicon wafers before film deposition, a film deposition heater 13B that heats the film deposition trays 1, a plurality of

gas nozzles

13A, 13B, and 13C that blow a source gas onto the silicon wafers 5, a loading/unloading mechanism 14 that delivers the silicon wafers 5 to the film deposition trays 1 at a loading/unloading position 14A, and a circulating mechanism 15 that circulates the film deposition trays 1 after film deposition to the loading/unloading position 14A along a circulation conveyance path 15A.

As shown in fig. 1, the film formation transport path 11A extends in the horizontal direction, and transports the film formation tray 1 on which the silicon wafers 5 are mounted along the film formation transport path 11A.

The film formation transport path 11A is continuous from a loading/unloading position 14A where the silicon wafer 5 is placed on the film formation tray 1 to the start point of the circulation transport path 15A through a preheating chamber 12 provided with a preheating heater 12a and a film formation chamber 13 provided with a film formation heater 13B and

gas nozzles

13A, 13B, and 13C.

The film formation tray 1 is conveyed by a film formation tray driving mechanism 11 provided in the film formation conveyance path 11A in a state where its main surface is along the film formation conveyance path 11A.

As shown in fig. 1, the film formation tray drive mechanism 11 includes

drive rollers

11A and 11b having axes in a horizontal direction perpendicular to the film formation conveyance path 11A so as to be spaced apart from each other along the film formation conveyance path 11A, and a drive belt 11c wound around the

drive rollers

11A and 11 b.

The drive belt 11c is called a belt, but is actually an endless track-like member made of metal or the like, and the shape thereof is not limited to the so-called belt.

As shown in fig. 1, a plurality of driving convex portions 11m that engage with driving concave portions 2m of a lower surface 2j of a film formation tray 1 (a lower surface of a tray main body 2) to be described later to drive the film formation tray 1 are provided above the driving belt 11c so as to protrude at predetermined intervals along the film formation conveyance path 11A.

In the drive belt 11c, the distance between the adjacent drive convex portions 11m and the drive convex portions 11m along the film formation conveyance path 11A is set to be substantially equal to the dimension in the conveyance direction of the film formation trays 1, and the adjacent film formation trays 1 driven by the drive belt 11c are arranged so as to be separated from each other to the extent of being in contact with each other.

An opening or a vertically penetrating portion is provided in the drive belt 11c between the adjacent drive convex portions 11m and the drive convex portions 11m, so that most of the lower surface 1b of the film formation tray 1 driven by the drive belt 11c supporting the end of the film formation tray 1 is exposed downward.

The film formation tray drive mechanism 11 moves the wound drive belt 11c in the horizontal direction (rightward in the drawing) by driving the

drive rollers

11a and 11 b. Thus, the film formation tray 1 on which the silicon wafer 5 newly supplied is placed is circulated by the driving belt 11c at the start point of the film formation conveyance path 11A.

At this time, the driving convex portion 11m engages with the driving concave portion 2m of the lower surface 1b of the film formation tray 1 as the driving belt 11c moves. Thus, the driving force of the driving belt 11c is transmitted from the driving convex portion 11m to the film formation tray 1, and the interval between the film formation trays 1 aligned on the driving belt 11c and the film formation tray 1 is also controlled by the arrangement interval of the driving convex portion 11m on the driving belt 11 c.

The film formation tray driving mechanism 11 is not limited to the belt driving system, and other mechanisms may be used. For example, the following structure is also possible: a mechanism for restricting the movement of the film formation trays 1 is provided along the film formation conveyance path 11A, the drive roller 11b is a cam, the drive convex portion 11m provided on a hook connected to the cam is engaged with the drive concave portion 2m of the lower surface 1b of the film formation tray 1 placed at the start point (left end in fig. 1) of the film formation conveyance path 11A, and the film formation trays 1 are pushed in the horizontal direction (rightward in the drawing) by the rotation of the cam, whereby the adjacent film formation trays 1 are sequentially pushed in the horizontal direction (rightward in the drawing), and the film formation trays 1 in contact with each other are moved along the film formation conveyance path 11A.

As shown in fig. 1, a preheating heater 12a and a film formation heater 13b are disposed below a drive belt 11c on which the film formation tray 1 is mounted, with

quartz plates

12s and 13s interposed therebetween. The

quartz plates

12s, 13s are provided for the following purposes: the heat from the preheating heater 12a and the film formation heater 13b can be transmitted to the lower surface of the film formation tray 1 placed on the driving belt 11c, and contamination of the heated silicon wafer 5 can be prevented.

The quartz plate 12s and the preheating heater 12a are the bottom position of the preheating chamber 12, and the quartz plate 13s and the film formation heater 13b are the bottom position of the film formation chamber 13. The preheating heater 12a and the film formation heater 13b are provided at positions below the film formation conveyance path 11A, and heat the film formation tray 1 from the lower surface side thereof.

As shown in fig. 1, the preheating chamber 12 and the film forming chamber 13 are provided adjacent to each other along the film forming conveyance path 11A, and the preheating chamber 12 and the film forming chamber 13 are covered with

covers

12k and 13k on the upper side and the side.

Both the preheating heater 12a and the film formation heater 13b are resistance-heated, and can heat the film formation tray 1 to a desired temperature.

In the film forming chamber 13, as shown in fig. 1,

gas nozzles

13A, 13B, and 13C are provided at positions above the film formation conveyance path 11A.

The gas showerhead 13A, the gas showerhead 13B, and the gas showerhead 13C have substantially the same configuration and are disposed at equal intervals along the film formation transport path 11A of the film formation chamber 13, and therefore the gas showerhead 13A will be described. In the showerhead 13B and the showerhead 13C, the reference numeral 13A of the showerhead 13A is replaced with

reference numerals

13B and 13C, and the description thereof is omitted.

The showerhead 13A is supplied with a source gas containing at least silicon (Si) and oxygen (O) and discharges the source gas into the film forming chamber 13. Further, a carrier gas or the like may be supplied to the showerhead 13A.

The source gas supplied to the showerhead 13A is preferably monosilane (SiH)₄) With oxygen (O)₂) Or tetraethoxysilane (TEOS, chemical formula: si (OC)₂H₅）₄) With ozone (O)₃) Or a mixture of these with N as a carrier gas₂The mixed gas of (1).

As shown in fig. 1, the showerhead 13A is a showerhead having a plurality of slit nozzles (opening portions) 13Aa to 13Af, and the plurality of slit nozzles (opening portions) 13Aa to 13Af have a length dimension equal to or larger than the maximum width (radial dimension) of the silicon wafer 5 in the width direction of the film formation transport path 11A.

As shown in fig. 1, the slit nozzles 13Aa to 13Af are arranged in parallel in a direction (lateral direction) orthogonal to the moving direction of the film formation tray 1, that is, so as to extend in the width direction of the film formation conveyance path 11A. The slit nozzles 13Aa to 13Af are arranged at intervals in the moving direction (longitudinal direction) of the film formation tray 1, that is, the arrangement width dimension along the film formation conveyance path 11A is set to about several mm.

As shown in fig. 1, the source gas slit nozzles 13Aa and 13Ab are provided in 2 pieces at the center position in the film formation transport path 11A of the showerhead 13A in the transport direction (vertical direction). The dimensions of the source gas slit nozzles 13Aa and 13Ab in the width direction of the film formation transport path 11A are set to be about several mm.

The source gas slit nozzles 13Aa and 13Ab are connected to the source gas supply portion 13f, and eject the source gas and the carrier gas supplied from the source gas supply portion 13f downward.

As shown in fig. 1, the discharge ports (slit nozzles) 13Ac and 13Ad are provided at positions on both sides of the raw material gas slit nozzles 13Aa and 13Ab, which are on the outer side in the transport direction (vertical direction) of the film formation transport path 11A. The discharge ports (slit nozzles) 13Ac and 13Ad are each set to have a dimension of about several mm in the width direction along the film formation conveyance path 11A.

The gas discharge portions 13g are connected to discharge ports (slit nozzles) 13Ac and 13Ad, respectively, and discharge the used gas to the gas discharge portions 13 g.

Further, as shown in fig. 1, the gas shielding portions (slit nozzles) 13Ae and 13Af are arranged at both outer positions in the film formation conveyance path 11A in the conveyance direction (longitudinal direction) of the discharge ports 13Ac and 13 Ad. The gas shielding portions (slit nozzles) 13Ae and 13Af are each set to have a dimension of about several mm in the width direction along the film formation conveyance path 11A.

The gas shielding parts (slit nozzles) 13Ae and 13Af are connected to the off-gas supply part 13h, and N supplied from the off-gas supply part 13h₂The blocking gas such as gas is blown downward to block the gas.

In the showerhead 13A, the source gas and the carrier gas supplied from the source gas supply section 13f and ejected from the source gas slot nozzles 13Aa and 13Ab form an oxide film on the surface 5a of the silicon wafer 5 being transported at the lower positions thereof. Then, the remaining residual raw material gas, carrier gas, is discharged to the gas discharge portion 13g through the discharge ports 13Ac, 13 Ad. While the raw gas is being discharged, N supplied from the blocking gas supply unit 13h₂Blocking gas such as gas is blown downward from the gas shielding portions (slit nozzles) 13Ae and 13Af to block the raw material gas from leaking outward.

As shown in fig. 1, the loading/unloading position 14A is located upstream of the film formation conveyance path 11A in the conveyance direction, and a loading/unloading mechanism 14 is disposed.

The loading/unloading mechanism 14 is a mechanism for placing the silicon wafer 5 carried in from the outside onto the film formation tray 1, or for carrying out the silicon wafer 5 after the film formation from the film formation tray 1 to the outside.

As shown in fig. 1, the loading/unloading mechanism 14 includes a plurality of support pins 14a that can support the silicon wafer 5 in a state where the film formation tray 1 penetrates therethrough and can be driven in the vertical direction, a support pin driving unit 14b that drives the support pins 14a in the vertical direction, and a transport unit 14c such as a robot that transports the silicon wafer 5 supported by the support pins 14a driven by the support pin driving unit 14b to the raised position to the outside.

As will be described later, the film formation tray 1 is provided with a plurality of pin through

holes

2p and 2p through which the support pins 14a and 14a can pass.

In the loading/unloading mechanism 14, the silicon wafer 5 is placed on and lifted up with respect to the film formation tray 1 by moving the support pins 14a, 14a up and down, and the silicon wafer 5 is transferred to the outside by the transfer unit 14c of the silicon wafer 5 supported by the lifted

support pins

14a, 14 a.

As shown in fig. 1, the circulation transport path 15A is a path for circulating the silicon wafer 5 after film formation and the film formation tray 1 on which the silicon wafer 5 is placed from the end point of the film formation transport path 11A to the loading/unloading position 14A which is the start point of the film formation transport path 11A.

The silicon wafer 5 after the film formation is transported through the circulation transport path 15A and cooled to a temperature at which it is taken out to the outside.

The circulation conveyance path 15A is constituted by the circulation mechanism 15, and in the present embodiment, as shown in fig. 1, is set so as to descend from the vicinity of the end point of the film formation conveyance path 11A by the

descent circulation units

15A, 15b, and 15c, return in the horizontal direction opposite to the film formation conveyance path 11A by the horizontal circulation unit 15d, and further ascend to the loading/unloading position 14A by the

ascent circulation units

15e, 15f, and 15 g.

The circulating transport path 15A is not limited to this configuration as long as it can circulate and transport the film formation tray 1 to the film formation transport path 11A, and may be configured to circulate and transport the film formation tray 1 in a plane substantially identical to the plane of the film formation transport path 11A.

As shown in fig. 1, the descending

circulation units

15a, 15b, and 15c include a descending lift 15a that receives the film formation tray 1 from the drive belt 11c in the vicinity of the end point of the film formation conveyance path 11A and mounts the film formation tray 1 thereon, a position regulating unit 15b that regulates the movement direction of the descending lift 15a in the vertical direction, and a descending drive unit 15c that drives the descending lift 15a in a state regulated by the position regulating unit 15 b.

As shown in fig. 1, the lowering elevator 15a receives the film formation tray 1 from the drive belt 11c in a state where the drive unit 15c for lowering is placed at its raised position, and delivers the film formation tray 1 to the horizontal circulating unit 15d in a state where the drive unit 15c for lowering is placed at its lowered position. The film formation tray 1 can be conveyed in the vertical direction between the raised position and the lowered position. When the film formation tray 1 is conveyed from the raised position to the lowered position, the lowering drive unit 15c drives the lowering lifter 15a to the raised position, and waits for the next film formation tray 1 to be received.

The horizontal circulating unit 15d receives the film formation tray 1 from the lowering lifter 15a set to the lowering position by the lowering drive unit 15c, mounts the film formation tray 1 thereon, and conveys the film formation tray in a horizontal direction which is a direction returning in a direction opposite to the film formation conveying path 11A.

The horizontal circulating unit 15d may be an endless belt or the like that can be horizontally conveyed by placing the film formation tray 1 thereon, but is not limited to this configuration.

The film formation trays 1 placed on the horizontal circulating unit 15d are set so that the interval between adjacent ones in the transport direction is larger than that in the film formation carried on the drive belt 11 c. This is because the circulation conveyance path 15A also serves as a cooling conveyance path for the film formation tray 1 and the silicon wafer 5 after film formation.

The ascending

circulation units

15e, 15f, and 15g are configured to correspond to the descending

circulation units

15a, 15b, and 15c, and include an ascending lift 15e that receives the film formation tray 1 from the horizontal circulation unit 15d in the vicinity of the end point of the horizontal circulation unit 15d and places the film formation tray 1 thereon, a position regulating unit 15f that regulates the movement direction of the ascending lift 15e in the vertical direction, and an ascending drive unit 15g that drives the ascending lift 15e in a state regulated by the position regulating unit 15 f.

The elevating lifter 15e receives the film formation tray 1 from the horizontal circulating unit 15d in a state where the elevating drive unit 15g is located at the lowered position, and becomes a loading/unloading position 14A where the silicon wafer 5 is transferred to the loading/unloading mechanism 14 in a state where the elevating drive unit 15g is located at the raised position, and can convey the silicon wafer in the vertical direction between the lowered position and the raised position. When the film formation tray 1 is conveyed from the lowered position to the raised position, the raising drive unit 15g drives the raising elevator 15e to the lowered position, and waits for the next film formation tray 1 to be received.

The film deposition apparatus 10 according to the present embodiment is configured to place a silicon wafer 5 carried in from the outside on a circulating film deposition tray 1 at a loading/unloading position 14A, transport the silicon wafer to a film deposition transport path 11A, heat the silicon wafer to a predetermined temperature in a preheating chamber 12, and eject a source gas in a separated state in a film deposition chamber 13, thereby performing a predetermined film deposition on the silicon wafer 5 to form a silicon oxide film in the present embodiment, and then transport the silicon wafer to a circulating transport path 15A to cool the silicon wafer 5 and the film deposition tray 1, and carry the silicon wafer 5 out to the outside at the loading/unloading position 14A which is circulated back.

Next, the film formation tray according to the present embodiment will be described with reference to the drawings.

Fig. 2 is a plan view showing a film formation tray according to the present embodiment, fig. 3 is a front sectional view showing the film formation tray according to the present embodiment, and reference numeral 1 in the drawing is a film formation tray.

The film formation tray 1 of the present embodiment is continuously transported in the film formation transport path 11A, and used in a film formation apparatus 10 that performs film formation on a silicon wafer 5 mounted thereon by blowing a raw material gas from a plurality of gas nozzles 13A to 13C, and is configured by a tray main body 2 and a support ring 3 that is erected on the tray main body 2 and supports the outer circumferential position of the silicon wafer 5, as shown in fig. 2 and 3.

Fig. 6 is a plan view showing the tray main body of the present embodiment, and fig. 7 is a sectional view showing the tray main body in fig. 6.

As shown in fig. 2, 3, 6, and 7, the tray main body 2 has a rectangular plate-like outline in a plan view, and a concave receiving portion 2w is formed on an upper surface 2c thereof, and the receiving portion 2w receives the support ring 3 having a circular shape in a plan view in accordance with a plan outline of the silicon wafer 5.

In the outline of the tray main body 2, the long side extends in the direction (lateral direction) orthogonal to the moving direction of the film formation tray 1, and the short side extends in the moving direction (longitudinal direction) of the film formation tray 1, and further, the film formation tray 1 can be heated in a state where a plurality of the long sides are close to each other.

The thickness of the tray body 2 is set to be in the range of 5 to 10 mm. This makes it possible to achieve a sufficient temperature increase with respect to the heating by the film formation heater 13b, maintain the uniformity of the temperature increase with respect to the silicon wafer 5, and have sufficient strength with respect to the support and conveyance of the silicon wafer 5 and the backup ring 3.

The inner peripheral surface 2b of the receiving portion 2w is an inclined surface extending outward in the upward direction, and is configured to minimize a contact state with the backup ring 3 as described later.

A plurality of pin through

holes

2p and 2p through which support pins 14a and 14a driven in the vertical direction can pass are provided on the surface 2a of the receiving portion 2 w.

A plurality of grooves 2f are intermittently provided around the bottom outer peripheral position of the receiving portion 2w, that is, the lower end position of the inner peripheral surface 2b of the bridge backup ring 3. A plurality of protruding portions 2e are formed at portions sandwiched by the plurality of grooves 2f in the circumferential direction.

Thus, the region corresponding to the groove 2f does not contact the backup ring 3 in the circumferential direction, and the region corresponding to the protruding portion 2e contacts the backup ring 3, so that the contact area between the backup ring 3 and the pallet body 2 can be reduced.

A driving concave portion 2m is provided on the lower surface 2j of the tray main body 2, and the driving concave portion 2m is engaged with the driving convex portion 11m of the film formation tray driving mechanism 11 as a state in which a plurality of sheets are continuously arranged and receives a driving force from the driving convex portion 11m when being conveyed by the film formation conveying path 11A.

According to the tray main body 2 of the present embodiment, it is possible to improve the heating efficiency from the film formation heater 13b, to improve the uniformity of the temperature state in the surface of the silicon wafer 5 in the moving direction (longitudinal direction) of the film formation transporting path 11A, and to improve the uniformity of the temperature state of the plurality of silicon wafers 5, thereby improving the film formation characteristics.

Further, the gas nozzles 13A to 13C have the openings (nozzles) 13Aa to 13Cf extending in the direction (transverse direction) orthogonal to the moving direction of the film formation tray 1, and when the raw material gas is ejected over the entire length in the transverse direction of the moving silicon wafer 5, unnecessary film formation between the film formation trays 1 can be reduced, generation of particles in the film formation apparatus 10 can be reduced, and adverse effects on film formation can be reduced.

Fig. 4 is a plan view showing the backup ring according to the present embodiment, and fig. 5 is a sectional view showing the backup ring in fig. 4.

As shown in fig. 2 to 5, the support ring (support member) 3 is in the shape of a ring having a slightly smaller radial dimension than the receiving portion 2w so as to be fitted into the receiving portion 2w of the tray main body 2.

As shown in fig. 2 to 5, the backup ring 3 includes: a placing part 3c for directly placing the silicon wafer 5, which is formed in a stepped shape at an upper position of an inner periphery thereof via a sidewall 3h descending from the upper surface 3a to the inner side and projects from the sidewall 3h toward a center side; a support portion (leg portion) 3f circumferentially provided to project downward as a lower position of an outer periphery of the backup ring 3; and a mounting portion lower surface 3d provided below the mounting portion 3c so as to be separated from the upper surface 2c of the tray main body 2 in accordance with the height dimension of the support portion (leg portion) 3 f.

The arithmetic mean roughness Ra of the surface of the placing part 3c of the support ring 3 on which the silicon wafer 5 is placed is set to be in the range of 0.01 to 2.0 μm. When the surface roughness Ra is smaller than this range, the silicon wafer 5 and the mounting portion 3c are bonded, which is not preferable, and when the surface roughness Ra is larger than this range, a gap is formed between the silicon wafer 5 and the mounting portion 3c, which decreases the sealing performance, and there is a possibility that the raw material gas or the like may pass through the gap into the space between the silicon wafer 5 and the tray main body 2 (the side of the rear surface 5c of the silicon wafer 5).

In order to set the surface roughness Ra of the mounting portion 3c to the above range, a treatment such as polishing, sandblasting, etching, or the like may be performed.

The ratio of the heat capacity of the backup ring 3 to the inner diameter R3c (heat capacity/inner diameter) is set to be in the range of 1.2 to 5.5 (J/K)/cm.

If the ratio of the heat capacity of the backup ring 3 to the silicon wafer 5, that is, the ratio of the heat capacity to the inner diameter of the placing part 3c is larger than the above range, the temperature of the silicon wafer 5 may decrease when the raw material gas is introduced, and in this case, the temperature of the placing part 3c of the backup ring 3 does not follow the decrease, and as a result, the temperature of the outer peripheral part of the silicon wafer 5 becomes higher than that of the central part, and the in-plane uniformity of the film formation may deteriorate, which is not preferable.

Further, if the ratio of the heat capacity to the inner diameter of the mount portion 3c is smaller than the above range, the volume of the backup ring 3 becomes too small, so that the strength cannot be maintained, the manufacture of the backup ring 3 becomes difficult, and the temperature distribution in the tray main body 2 reflecting the temperature distribution of the film formation heater 13b also affects the temperature distribution of the mount portion 3c of the backup ring 3, so that the in-plane uniformity of the film formation may be deteriorated, which is not preferable.

As shown in FIG. 4, the supporting ring 3 has a ratio (outer diameter/inner diameter) of the outer diameter R3a to the inner diameter R3c of the mounting portion 3c set in a range of 1.02 to 1.10.

Here, if the ratio of the outer diameter to the inner diameter of the backup ring 3, that is, the width dimension of the backup ring 3, is small, the tray main body 2 and the outer peripheral portion of the silicon wafer 5 are too close to each other, and therefore the influence of the heat transfer plus the radiant heat becomes large, and the temperature of the outer peripheral portion of the silicon wafer 5 may become high, which is not preferable.

Further, if the width dimension of the backup ring 3, which is the ratio, is too large, it is necessary to make the thickness thereof small in order to reduce the heat capacity, and the backup ring 3 is deformed due to insufficient rigidity, or the volume of the backup ring 3 becomes too small, so that the strength cannot be maintained and the manufacturing of the backup ring 3 becomes difficult, which is not preferable.

Further, the thickness dimension T3d of the backup ring 3, i.e., the dimension T3d from the mounting portion lower surface 3d to the uppermost surface 3a as shown in fig. 5, is set to be in the range of 0.4 to 1.10 mm. The thickness dimension T3d does not include the leg (support portion) 3 f.

Here, if the thickness dimension T3d is too large, it takes too much time to form large SiC and uniformity in the large block may be degraded in the production of the backup ring 3 described later, which is not preferable.

Further, if the thickness dimension T3d is too thick, the heat capacity of the placement portion 3c becomes too large, and even if the temperature of the silicon wafer 5 decreases, the temperature of the placement portion 3c does not follow the decrease, and the temperature of the outer peripheral portion of the silicon wafer 5 becomes higher than that of the central portion, and there is a possibility that the in-plane uniformity of film formation is deteriorated, which is not preferable, and if the thickness dimension T3d is too large, the heat capacity is set, and the tray main body 2 and the outer peripheral portion of the silicon wafer 5 are too close, and there is a possibility that the temperature of the outer peripheral portion of the silicon wafer 5 becomes too high.

Furthermore, if the thickness dimension T3d is too small, the rigidity is insufficient, the backup ring 3 deforms, and the volume of the backup ring 3 becomes too small, so that the strength cannot be maintained, and the backup ring 3 is difficult to manufacture, and the temperature distribution in the tray main body 2 reflecting the temperature distribution of the film formation heater 13b also affects the temperature distribution of the mounting portion 3c, so that the in-plane uniformity of the film formation may deteriorate, which is not preferable. Further, if the thickness dimension T3d is too small, the tray main body 2 and the silicon wafer 5 come too close to each other, and therefore, the influence of radiation heat is large in addition to the influence of conduction heat, which is not preferable.

This makes it possible to set the heat capacity and the width dimension of the backup ring 3 within preferable ranges.

As shown in fig. 5, the height dimension T3c, i.e., the depth dimension T3c of the placing portion 3c can be set to be equal to or less than the thickness of the silicon wafer 5 by setting the height dimension T3c from the upper surface of the placing portion 3c to the uppermost surface 3a to be in the range of 0.2 to 0.6 mm. Thereby, the silicon wafer 5 can be positioned higher than the uppermost surface 3a of the backup ring 3 and the uppermost surface 2c of the tray main body 2. Therefore, the raw material gas ejected onto the silicon wafer 5 flows out toward the periphery and further flows from the uppermost surface 3a of the backup ring 3 toward the uppermost surface 2c of the tray main body 2, and the gas flow is not disturbed.

On the other hand, when the depth dimension T3c of the placing part 3c is equal to or greater than the thickness of the silicon wafer 5, the raw material gas collides with the side wall 3h of the placing part 3c of the backup ring 3 to generate turbulence, and the film thickness may be uneven at the outer peripheral part of the silicon wafer 5. When the height dimension T3c, i.e., the depth dimension of the placement portion 3c, is smaller than the above range, the raw material gas tends to bypass the back surface side of the outer peripheral portion of the silicon wafer 5, i.e., the chamfered portion side of the silicon wafer 5, and the placement portion 3c and the silicon wafer 5 are likely to be bonded to each other, which is not preferable.

Next, a method for manufacturing the film formation tray according to the present embodiment will be described.

Fig. 8 is a sectional view showing a manufacturing process of the backup ring according to the present embodiment, and fig. 9 is a sectional view showing a manufacturing process of the backup ring according to the present embodiment.

The backup ring 3 of the present embodiment is cut out from a ceramic that is grown from a gas phase and becomes SiC in bulk.

Specifically, the method comprises: a step of growing a ceramic, which is SiC, in a vapor phase on a predetermined production substrate (substrate) 3S to form a bulk; and a cutting step of cutting out a predetermined portion from the bulk SiC ceramic to form the mounting portion 3 c.

In the method for manufacturing the backup ring 3 according to the present embodiment, first, as a vapor phase growth step, as shown in fig. 8, a manufacturing substrate 3S, for example, SiC, is placed in a heating zone, and a gas containing a silicon component and a carbon component, for example, monosilane (SiH) is introduced as a raw material gas onto the manufacturing substrate 3S₄) And propane (C)₃H₈) A laminated body (bulk) 3A of SiC is deposited on the substrate 3S by a Chemical Vapor Deposition (CVD) method. In this case, the large block 3A may be formed only in a region corresponding to the loop-shaped portion shown in fig. 4, or may be formed in a large region of the manufacturing substrate 3S including the loop-shaped portion shown in fig. 4.

Next, a large loop body 3B corresponding to the loop shape shown in fig. 4 is formed. At this time, as shown in fig. 9, the ring body 3B may have a substantially rectangular cross-sectional shape including a surface corresponding along the upper surface 3a, a surface serving as the inner front end of the placement portion 3c, and two surfaces serving as the support portions (leg portions) 3 f.

Further, as a cutting-out step, as shown in fig. 9, the ring body 3B is cut out to the mounting portion lower surface 3d on the back side which is the upper side in the drawing so as to leave the supporting portion (leg portion) 3f, and the portion inside the side wall 3h is cut out to the mounting portion 3c on the front side which is the lower side in the drawing, and surface treatment is performed so that the surface state of the mounting portion 3c, particularly the surface roughness Ra, is within the above range.

Here, as the grinding treatment for the ring body 3B, a normal processing method for ceramics can be adopted, but fixed abrasive grain grinding is preferable.

Thereby, the backup ring 3 can be manufactured.

Fig. 10 is a process diagram showing a manufacturing process of a tray body according to the present embodiment, fig. 11 is a process diagram showing a manufacturing process of a tray body according to the present embodiment, fig. 12 is a process diagram showing a manufacturing process of a tray body according to the present embodiment, fig. 13 is a process diagram showing a manufacturing process of a tray body according to the present embodiment, fig. 14 is a cross-sectional view showing a manufacturing process of a tray body according to the present embodiment, and fig. 15 is a process diagram showing a manufacturing process of a tray body according to the present embodiment.

The tray main body 2 of the present embodiment is made of powder sintered ceramics of SiC.

Specifically, the method includes a sintering step of sintering the powder to form a ceramic sintered body 2E as SiC, and a step of vapor-phase growing a ceramic film 2Fa as SiC on the surface.

In the method for manufacturing the pallet body 2 according to the present embodiment, as a sintering step by the Reaction Sintering (RS) method, raw material powder is first prepared. As the raw material powder, for example, SiC powder having a particle diameter of a micron order, C powder (carbon black) of a submicron order, and metal Si are used. First, as shown in fig. 10, SiC powder 2a1 and C powder 2a2 were mixed to prepare a mixed powder.

The prepared powder 2B is pressed by a die P as shown in fig. 11 to be formed into a shape corresponding to the tray main body 2. Here, in addition to the mold pressing P, Cold Isostatic Pressing (CIP), extrusion molding, injection molding, cast molding, pressure cast molding, or the like can be employed.

Next, as shown in fig. 12, the compact 2C and the metal Si2C1 are charged into the crucible Cc, the inside of the chamber Cd is set to a reduced pressure atmosphere or an inert gas atmosphere, and the chamber Cd is heated by the heater Ch to a temperature equal to or higher than the melting point of the metal Si, so that the compact 2C is impregnated with the molten metal Si and reaction-sintered, thereby obtaining a compact 2D impregnated with Si, as shown in fig. 13.

Next, as shown in fig. 13, the sintered body 2D is formed into a finished body 2E having an outer shape corresponding to the pallet body 2 by polishing.

Finally, the SiC film 2Fa is attached to the surface of the finished product 2E by CVD, thereby completing the pallet body 2.

Thereby, the tray main body 2 can be manufactured.

In addition, in the tray main body 2, there may be:

density; 3.1 (kg/cm)³）

A bending strength; 300 (MPa)

Young's modulus; 400 (GPa)

Breaking the toughness; 3.3 (MPa ･ m)^1/2）

Hardness; 2,000 (Hv)

Thermal conductivity; 130 (W/m ･ K)

Specific heat; 6.8(10²J/kg･K）

Coefficient of thermal expansion; 4.5(10^－6and/K) (room temperature-1073K).

Further, in the backup ring 3, there may be:

density; 3.2 (kg/cm)³）

A bending strength; 600 (MPa)

Young's modulus; 450 (GPa)

Breaking the toughness; 3.3 (MPa ･ m)^1/2）

Hardness; 2,000 (Hv)

Thermal conductivity; 250 (W/m ･ K)

Specific heat; 6.8(10²J/kg･K）

Coefficient of thermal expansion; 3.9(10^－6and/K) (room temperature-1073K).

According to the present embodiment, the tray body 2 having the SiC film formed by CVD on the surface of the Si-impregnated SiC sintered body and the backup ring 3 formed of SiC cut out from the bulk formed by CVD can prevent the occurrence of cracks and the deterioration of the manufacturing yield of the backup ring 3.

Specifically, the production yield cannot exceed 50% in the conventional production method for forming a SiC film on the surface of a Si-impregnated SiC sintered body by CVD, and the production yield can exceed 80% in the backup ring 3 of the present embodiment.

According to the present embodiment, the thickness distribution of the oxide film formed on the silicon wafer 5 can be made uniform within a range of ± 10% in the wafer plane with respect to the target value of the oxide film thickness.

Hereinafter, a film formation tray (CVD tray) and a film formation method according to embodiment 2 of the present invention will be described with reference to the drawings.

Fig. 16 to 19 are views showing an embodiment composed of a tray main body and a backup ring according to the present invention, respectively, fig. 16 shows a case where the tray main body has a receiving portion, fig. 17 shows a case where a flat tray main body is used to support the backup ring on the outer periphery, fig. 18 shows a case where a flat tray main body is used to support the backup ring on the middle portion, and fig. 19 shows a case where a concave portion is provided on the surface of the tray main body facing the silicon wafer. The tray 1 shown in fig. 16 to 19 is composed of a tray main body 2 and a support ring 3, and a silicon wafer 5 is supported and placed by a placing part 3c provided in the support ring 3.

The film forming tray of the present embodiment is used for film forming by a CVD method, and is a film forming tray 1 comprising a tray main body 2 and a support ring 3 that is bridged over the tray main body 2 and supports a silicon wafer 5, wherein a placing part 3c for directly placing the silicon wafer 5 is provided on the support ring 3, and further, the placing part 3c has a placing part lower surface 3d separated from a surface 2a of the tray main body, and the surface 2a of the tray main body faces the placed silicon wafer with a distance.

Since the lower surface 3d is provided on the placement portion 3c on which the silicon wafer 5 is directly placed, and the placement portion 3c is separated from the surface 2a of the tray main body facing the silicon wafer, the amount of heat held by the tray main body 2 that is transferred to the placement portion 3c can be reduced, and therefore, the heat transfer from the tray 1 to the outer peripheral portion 5b of the silicon wafer can be reduced. Thus, when the film is formed by the atmospheric pressure CVD method, the temperature rise near the outer peripheral portion of the silicon wafer can be reduced, and the thickness of the oxide film formed on the silicon wafer can be made uniform.

The embodiment shown in fig. 16 to 18 can be adopted in order to provide the lower surface 3d on the placing portion 3c of the backup ring 3 and separate the placing portion 3c from the surface 2a of the tray main body facing the silicon wafer. Fig. 16 shows an embodiment in the case of using a tray main body having a concave receiving portion for receiving and erecting a support ring, and fig. 17 and 18 show an embodiment in the case of using a planar tray main body. The film forming tray of the present invention is not limited to the embodiment shown in fig. 16 to 18, and various structures may be adopted to separate the mounting portion 3c from the tray main body.

The film forming tray of the present embodiment preferably has a structure in which the contact area between the backup ring and the tray main body is reduced.

In the trays shown in fig. 16 to 19, if heat is conducted from the tray main body to the backup ring when the trays are used for film formation by the atmospheric pressure CVD method, the heat may be conducted to the silicon wafer placed on the backup ring. In this case, the portion of the silicon wafer in contact with the placing portion of the backup ring and the vicinity thereof become high temperature, and the thickness distribution of the oxide film formed on the silicon wafer becomes uneven.

Here, of the heat conducted from the tray main body to the backup ring, the proportion of the heat conducted from the portion where the tray main body and the backup ring are in contact is large. Therefore, by configuring the tray such that the contact area between the backup ring and the tray main body is reduced, the amount of heat held by the tray main body that is conducted to the backup ring can be reduced. This can suppress the heat of the tray main body from being conducted to the backup ring and the temperature rise in the portion of the silicon wafer in contact with the backup ring and the vicinity thereof, and as a result, the thickness of the oxide film formed on the silicon wafer can be made more uniform.

As a method for suppressing the temperature rise in the portion of the silicon wafer in contact with the backup ring and the vicinity thereof due to the heat conducted from the portion of the tray main body in contact with the backup ring, a method for increasing the distance from the portion of the backup ring in contact with the tray main body to the placement portion may be considered. However, in order to increase the distance from the portion of the backup ring in contact with the tray main body to the placement portion, it is necessary to use a tray main body and a backup ring which greatly exceed the diameter of the silicon wafer to be placed.

In this case, in the normal pressure CVD method in which film formation is continuously performed usually using a conveyor, if the tray is increased in size, productivity is deteriorated, which is a problem, and further, a significant modification of the CVD apparatus used for film formation is required, which is a problem in that equipment cost is increased. If the above-described tray is configured such that the contact area between the backup ring and the tray main body is reduced, the thickness of the oxide film formed on the silicon wafer can be made more uniform without causing problems of deterioration in productivity and increase in equipment cost.

Embodiments 3 to 5 below show embodiments in which the film forming tray of the present invention can be used as a structure for reducing the contact area between the backup ring and the tray main body.

Hereinafter, a film deposition tray and a film deposition method according to embodiment 3 of the present invention will be described with reference to the drawings.

Fig. 20 to 21 are views showing an embodiment in which a protruding portion is provided on a tray main body, fig. 20 is a plan view, and fig. 21 is a sectional view taken along line XXI-XXI in fig. 20. The tray shown in fig. 20 to 21 is composed of a tray main body 2 and a support ring 3 which is erected on the tray main body 2 and supports a silicon wafer 5. The backup ring 3 is provided with a placing portion 3c on which the silicon wafer 5 is directly placed, and has a placing portion lower surface 3d separated from the tray main body 2.

The film forming tray of the present embodiment is characterized by having a structure in which a protruding portion 2e is provided on the tray main body 2 and the support ring 3 is bridged over the protruding portion 2e as a structure for reducing the contact area between the support ring 3 and the tray main body 2. In the pallet shown in fig. 20 to 21, 6 grooves 2f are provided in the pallet body 2 at the portion where the backup ring 3 is bridged as indicated by the broken line in the plan view of fig. 20, thereby forming 6 protruding portions 2 e. Therefore, the spider 3 does not contact the tray main body 2 in the region where the groove 2f is provided, but contacts the tray main body at the protruding portion 2e, so that the contact area of the spider 3 and the tray main body 2 can be reduced.

The film formation tray of the present embodiment is not limited to the embodiment shown in fig. 20 to 21, and an embodiment in which an inner peripheral surface of a receiving portion of the tray main body, which receives and spans the backup ring, is inclined or an embodiment in which a planar tray main body is used may be employed.

Hereinafter, a deposition tray and a deposition method according to embodiment 4 of the present invention will be described with reference to the drawings.

Fig. 22 to 24 are cross-sectional views showing an embodiment of the present invention in which a protruding portion is provided on a tray main body, fig. 22 shows a case where a planar tray main body is used, fig. 23 shows a case where the tray main body has a receiving portion, and fig. 24 shows a case where a concave portion is provided below a placement portion. In the pallet shown in fig. 22 to 24, although not shown, 6 grooves are provided in a portion of the pallet body where the support ring is provided, similarly to the pallet shown in fig. 20 to 21, thereby forming 6 protruding portions. Therefore, the spider 3 does not contact the tray main body 2 in the region where the groove 2f is provided, but contacts the tray main body at the protruding portion, so that the contact area of the spider and the tray main body can be reduced.

In this way, by providing the protruding portion in the tray main body and providing the support ring on the protruding portion, the contact area between the support ring and the tray main body can be reduced. Therefore, when the film formation tray of the present embodiment is used for film formation of a silicon wafer by the atmospheric pressure CVD method, the thickness distribution of the oxide film to be formed can be made more uniform.

In the film forming tray of the present embodiment, at least 3 protruding portions may be provided. The protruding portion may have various shapes as long as the support ring can be stably erected.

In the film formation tray of the present embodiment, as shown in fig. 23, when the tray main body 2 has a concave receiving portion for receiving the backup ring 3, it is preferable that an inner peripheral surface 2b of the receiving portion of the tray main body is formed as an inclined surface, and an upper portion thereof is disposed so as to be distant from a center of the receiving portion. Thus, the backup ring 3 does not contact most of the inner peripheral surface 2b of the concave receiving portion but comes into surface-line contact with the inner peripheral surface, so that the contact area between the backup ring 3 and the tray main body 2 can be further reduced.

As a structure for reducing the contact area between the inner peripheral surface of the receiving portion of the tray main body and the backup ring, a structure may be adopted in which the inner peripheral surface of the receiving portion of the tray main body is inclined and the lower portion thereof is disposed away from the center of the receiving portion. Further, a structure in which the face of the backup ring in contact with the inner peripheral face of the receiving portion is inclined, or a structure in which a plurality of grooves are provided in the inner peripheral face of the receiving portion or the face of the backup ring in contact with the inner peripheral face may be adopted. In the film forming tray of the present invention, since the manufacturing of the tray is easiest and the manufacturing cost can be suppressed, it is preferable to adopt a structure in which the inner peripheral surface of the receiving portion of the tray main body is inclined and the upper portion thereof is disposed away from the center of the receiving portion.

Hereinafter, a deposition tray and a deposition method according to embodiment 5 of the present invention will be described with reference to the drawings.

Fig. 25 to 26 are views showing an embodiment of the present invention in which a backup ring is bridged via point contact and line contact, fig. 25 is a plan view, and fig. 26 is a sectional view XXVI to XXVI of fig. 25. The tray shown in fig. 25 to 26 is composed of a tray main body 2 having a concave receiving portion for receiving the support ring 3, and the support ring 3 which is bridged over the tray main body 2 and supports the silicon wafer 5. The backup ring 3 is provided with a placing portion 3c on which the silicon wafer 5 is directly placed, and has a placing portion lower surface 3d separated from the tray main body 2.

The film forming tray of the present embodiment is characterized by having a structure in which the backup ring 3 is bridged over the tray main body 2 via point contact or line contact as a structure for reducing the contact area between the backup ring 3 and the tray main body 2. In the pallet shown in fig. 25 to 26, the support ring 3 includes a columnar stay portion 3e, and the lower portion of the stay portion 3e is conical, and the cross-sectional area thereof decreases as it approaches the lower end. As shown in fig. 25, the number of the support portions 3e is 6 on a circle concentric with the silicon wafer 5 placed thereon at a predetermined angular interval. The outer peripheral surface 3b of the backup ring that is in contact with the inner peripheral surface 2b of the receiving portion of the tray main body is inclined so that the lower portion thereof is spaced apart from the inner peripheral surface of the receiving portion of the tray main body.

When such a backup ring 3 is mounted on the tray main body 2, the backup ring 3 and the tray main body 2 are mounted via point contact using the lower ends of the plurality of column portions 3e provided in the backup ring 3 and line contact using the inclined outer peripheral surface 3b of the backup ring 3. Therefore, the contact area of the backup ring 3 and the tray main body 2 can be reduced. In the pallet shown in fig. 25 to 26, 6 column portions 3e are provided, but in the case where the support ring 3 is bridged over the pallet main body 2 via point contact using the column portions 3e of the support ring 3, at least 3 column portions 3e may be provided. The film forming tray of the present embodiment is not limited to the embodiment shown in fig. 25 to 26, and an embodiment using a planar tray main body or an embodiment in which a support ring is bridged via linear contact may be employed.

Hereinafter, a deposition tray and a deposition method according to embodiment 6 of the present invention will be described with reference to the drawings.

Fig. 27 to 28 are cross-sectional views each showing an embodiment of the present invention in which a support ring is bridged via line contact, fig. 27 shows a case in which the support ring is bridged via line contact on a tray main body having a concave receiving portion, and fig. 28 shows a case in which the support ring is bridged via line contact on a planar tray main body.

The tray shown in fig. 27 is composed of a tray main body 2 having a concave receiving portion for receiving the backup ring 3 and the backup ring 3. The placing part 3c and the silicon wafer 5 placed thereon are supported by a cylindrical support part 3f provided on the outer periphery of the support ring 3. In the tray shown in fig. 27, the inner peripheral surface 2b of the concave receiving portion of the tray main body is inclined so that the upper portion thereof is spaced apart from the center of the receiving portion, and the lower surface 3g of the cylindrical support portion provided on the backup ring 3 is inclined so that the inner peripheral side thereof is spaced apart from the surface 2a of the tray main body facing the silicon wafer 5.

Thus, in the pallet shown in fig. 27, most of the outer peripheral surface and the lower surface of the support portion 3f of the backup ring 3 do not contact the pallet main body 2, and are bridged over the pallet main body 2 via line contact with the lower end of the cylindrical support portion 3f of the backup ring 3. Therefore, the contact area of the backup ring 3 and the tray main body 2 can be reduced.

The pallet shown in fig. 28 is composed of a planar pallet body 2 and a support ring 3 provided with a cylindrical support portion 3 f. In the tray shown in fig. 28, the cylindrical support portion 3f of the support ring 3 has an inner peripheral surface and an outer peripheral surface inclined at a lower portion, and a cross-sectional area thereof is reduced as it approaches a lower end. Thus, the pallet shown in fig. 28 is erected by the lower end of the cylindrical support portion 3f of the support ring 3 coming into line contact with the planar pallet main body 2. Therefore, the tray shown in fig. 28 can reduce the contact area of the backup ring 3 and the tray main body 2.

In this way, by configuring the support ring to be bridged over the tray main body via point contact or line contact, the contact area between the support ring and the tray main body can be reduced. Therefore, when the film formation tray of the present embodiment is used for film formation of a silicon wafer by the atmospheric pressure CVD method, the thickness distribution of the oxide film to be formed can be made more uniform.

Hereinafter, a 7 th embodiment of a film deposition tray and a film deposition method according to the present invention will be described with reference to the drawings.

Fig. 29 to 30 are sectional views each showing an embodiment of the present invention in which a backup ring is bridged via point contact or line contact by a jig, fig. 29 shows a case in which the backup ring is bridged via point contact, and fig. 30 shows a case in which the backup ring is bridged via line contact. The tray shown in fig. 29 and 30 is composed of a tray main body 2, a support ring 3 for supporting a silicon wafer, and a jig 4 for supporting the support ring 3.

The film forming tray of the present embodiment is characterized by including a jig 4 for supporting the backup ring 3, and as a structure for reducing the contact area between the backup ring 3 and the tray main body 2, has a structure for mounting the backup ring 3 on the tray main body 2 via point contact or line contact by the jig 4. In the tray shown in fig. 29, the jig 4 has a cylindrical shape, and its upper portion is made into a conical shape, and the cross-sectional area decreases as it approaches the upper end. The columnar jig 4 is disposed on the surface 2a of the tray main body facing the silicon wafer placed thereon. In the tray shown in fig. 29, in addition to the 2 cylindrical jigs 4 shown in the drawing, 4 cylindrical jigs 4 not shown are arranged at predetermined angular intervals on a circle concentric with the silicon wafer 5 placed thereon, and the support ring 3 is erected using a total of 6 jigs.

In the pallet shown in fig. 29, a plurality of columnar jigs 4 are arranged on a pallet main body 2, and a support ring 3 is provided on the conical upper end of the columnar jigs 4. Therefore, since the support ring 3 is bridged over the tray main body 2 via the point contact by the jig 4, the contact area between the support ring 3 and the tray main body 2 can be reduced. In the pallet shown in fig. 29, 6 jigs 4 are arranged, but when the backup ring 3 is bridged over the pallet main body 2 via point contact using the jigs 4, at least 3 jigs 4 may be arranged.

In the case where the tray main body 2 has a concave receiving portion for receiving the backup ring 3 as shown in fig. 29, in order to reduce the contact area between the outer peripheral surface 3b of the backup ring and the inner peripheral surface 2b of the concave receiving portion of the tray main body, it is preferable that the outer peripheral surface 3b of the backup ring is formed as an inclined surface and the lower portion thereof is disposed so as to be spaced apart from the inner peripheral surface 2b of the receiving portion as shown in fig. 29.

Here, when the outer peripheral surface of the backup ring is formed as an inclined surface, the backup ring may be disposed so that the upper portion thereof is spaced apart from the inner peripheral surface of the receiving portion. In the method of disposing the upper portion of the receiving portion away from the inner peripheral surface of the receiving portion, when the raw material gas is supplied onto the silicon wafer by the CVD method to form a film, the flow of the raw material gas may be disturbed by the depression formed by the inclined surface, thereby adversely affecting the thickness distribution of the oxide film.

Further, the inner circumferential surface 2b of the receiving portion of the tray main body may be inclined. In this aspect, if the upper portion of the inner peripheral surface of the receiving portion is disposed so as to be distant from the center of the receiving portion, the flow of the raw material gas may be disturbed by the depression formed by the inclined surface, and the thickness distribution of the oxide film may be adversely affected. On the other hand, it is also conceivable to arrange the lower portion of the inner peripheral surface of the receiving portion so as to be away from the center of the receiving portion, but the manufacturing of the tray main body becomes difficult, and the manufacturing yield deteriorates.

If the outer peripheral surface of the backup ring is formed as an inclined surface and the lower portion thereof is disposed away from the inner peripheral surface of the receiving portion, it is possible to eliminate the concern about the thickness distribution of the oxide film due to the disturbance of the flow of the raw material gas, and the production of the tray is also facilitated. Therefore, in order to reduce the contact area between the outer peripheral surface of the backup ring and the inner peripheral surface of the receiving portion of the tray main body, it is preferable that the outer peripheral surface of the backup ring is formed as an inclined surface and the lower portion thereof is disposed away from the inner peripheral surface of the receiving portion.

The pallet shown in fig. 30 uses a cylindrical jig 4. The cylindrical jig 4 is arranged such that the upper surface of the jig in contact with the backup ring 3 is an inclined surface and the inner circumferential side is close to the surface 2a of the tray main body facing the silicon wafer 5. When the cylindrical jig 4 is disposed on the pallet main body 2 and the support ring 3 is stretched by the jig 4, the support ring 3 is stretched in a state of being in line contact with the upper end of the upper surface of the cylindrical jig 4. Therefore, the contact area of the backup ring 3 and the tray main body 2 can be reduced.

In this way, by providing the structure in which the support ring is bridged on the tray main body through point contact or line contact by the jig, the area of contact between the support ring and the tray main body via the jig can be reduced. Therefore, when the film formation tray according to embodiment 4 of the present invention is used for film formation of a silicon wafer by the atmospheric pressure CVD method, the thickness distribution of the oxide film to be formed can be made more uniform.

[ preferred embodiment for mounting part, etc. ]

The film forming tray of the present invention described above preferably adopts the following embodiments.

In the film formation tray of the present invention, in order to support the outer peripheral portion 5b of the silicon wafer 5, it is preferable that the placement portion 3c is formed as an inclined surface, and the inner peripheral side is disposed close to the surface 2a of the tray main body facing the placed silicon wafer 5 at a distance. This is because the silicon wafer can be supported without the non-film-formation surface 5c of the silicon wafer coming into contact with the tray, and therefore, the oxide film formed on the film-formation surface 5a of the silicon wafer can be made uniform in thickness without causing contact damage on the non-film-formation surface 5c of the silicon wafer.

In the film formation tray of the present invention, the mount portion 3c is preferably annular. In this case, the silicon wafer may be placed on the silicon wafer by supporting a plurality of portions of the outer peripheral portion of the silicon wafer by a plurality of placing portions divided at predetermined angles. In the case of film formation by the CVD method, if the source gas is caused to detour from the opening to the silicon wafer non-film-formation surface 5c to form a film, the temperature distribution of the silicon wafer film-formation surface 5a becomes uneven, and the oxide film thickness distribution may be deteriorated. Further, the amount of film formation on the non-film formation surface 5c of the silicon wafer is increased, and then the amount of removal by polishing is increased.

Since the silicon wafer 5 and the placing part 3c are in contact with each other over the entire circumference by forming the placing part 3c in a ring shape, the raw material gas can be prevented from bypassing the non-film-formation surface of the silicon wafer, and the above-mentioned fear can be eliminated.

As described above, the film formation tray needs not to be deformed by heating at the time of film formation and not to cause contamination on the silicon wafer. Further, in order to reduce heat conduction from the placing portion 3c to the silicon wafer outer peripheral portion 2b, it is preferable to make the placing portion 3c have a thin-walled structure with a thickness of 1mm or less. In the film formation tray of the present invention, in order to satisfy these requirements, the mounting portion 3c is preferably formed of SiC, and preferably, SiC alone, a material in which a SiC film by a CVD method is formed on the surface of a carbon substrate, or SiC film alone by a CVD method is formed, but the mounting portion 3c may be formed of a material other than SiC as long as the above requirements are satisfied.

In the film formation tray of the present invention, it is preferable that the height of the upper surface 3a of the support ring or the depth of the placing part 3c is adjusted so that the silicon wafer film formation surface 5a and the upper surface 3a of the support ring have the same height when the silicon wafer is placed. Further, when the tray main body has a concave receiving portion for receiving the backup ring, it is preferable that the silicon wafer deposition surface 5a and the upper surface 2c of the receiving portion have the same height when the silicon wafer is placed. This is because, if the height of the upper surface 3a of the backup ring or the upper surface 2c of the receiving portion is different from the height of the silicon wafer film formation surface 5a, the flow of the source gas supplied to the silicon wafer film formation surface is disturbed, the thickness of the oxide film formed on the film formation surface 5a is locally increased or decreased, and the thickness distribution becomes uneven.

In the film formation tray of the present invention, it is preferable that a concave portion further separated from the mounting portion is provided in a portion located below the mounting portion on a surface of the tray main body facing the silicon wafer to be mounted. As shown in fig. 19 or 24, by providing the concave portion 2d, which is further apart from the mounting portion, at the portion located below the mounting portion 3c, which is the surface 2a of the tray main body facing the silicon wafer to be mounted with a distance, it is possible to reduce the temperature rise of the mounting portion 3c due to the radiant heat from the surface 2a of the tray main body facing the silicon wafer. This can further reduce heat conduction from the placement portion 3c to the silicon wafer outer peripheral portion 5b, and further suppress temperature rise in the vicinity of the outer peripheral portion of the silicon wafer, thereby making the thickness of the oxide film formed on the silicon wafer deposition surface 5a more uniform.

[ film Forming method Using film Forming Pallet ]

The film forming method of the present invention is a film forming method using the film forming tray of the present invention. As described above, the film formation tray of the present invention is a tray in which the placement portion of the support ring for supporting the silicon wafer has a lower surface separated from the surface 2a of the tray main body, and the surface 2a of the tray main body faces the silicon wafer.

According to the film formation method of the present invention, an oxide film having a uniform thickness distribution can be formed on a silicon wafer by reducing heat conduction from a tray to the silicon wafer. Further, if the film formation tray of the present invention in which the placing portion is formed as an inclined surface is used, the outer peripheral portion of the silicon wafer is supported, so that the occurrence of contact damage to the surface of the silicon wafer can be reduced as much as possible.

[ examples ]

In order to confirm the effects of the film forming tray and the film forming method using the same according to the present invention, the following tests were performed.

[ test conditions ]

As inventive example 1, after a silicon wafer was placed on the tray shown in FIG. 16, the silicon wafer was heated by the film forming apparatus shown in FIG. 1, and a raw material gas was supplied onto the silicon wafer to form an oxide film (SiO) on the silicon wafer by the CVD method under normal pressure₂) Then, the thickness of the oxide film was measured.

In inventive example 1, a silicon wafer having a diameter of 300mm was tested by a continuous atmospheric pressure CVD system for forming an oxide film by a CVD method, and a raw material gas was monosilane (SiH)₄) With oxygen (O)₂) The silicon wafer was heated to 430 ℃ by heating the inside of the CVD apparatus with the mixed gas of (1), and an experiment was performed with the target oxide film thickness set to 3500 ANGSTROM.

The thickness of the oxide film was measured by spectroscopic ellipsometry so that the area excluding the outer periphery of the wafer was 5mm, and 121 sites in the wafer plane were measured.

As comparative example 1, after a silicon wafer was placed on the tray shown in fig. 35, an oxide film was formed on the silicon wafer by a CVD method under normal pressure in the same manner as in inventive example 1, and then the oxide film thickness was measured.

[ test results ]

Fig. 31 is a view showing the thickness distribution of an oxide film when the film is formed on a silicon wafer using the film formation tray of the present invention. According to the thickness distribution shown in FIG. 31, in example 1 of the present invention, the thickness distribution of the oxide film is 3400 to 3800 angstroms, and the width of the thickness distribution is about 400 angstroms.

Fig. 32 is a view showing the thickness distribution of an oxide film when a film is formed on a silicon wafer using a conventional tray for supporting the outer peripheral portion of the silicon wafer. According to the thickness distribution shown in FIG. 32, in comparative example 1, the thickness distribution of the oxide film was 3200 to 3900 angstroms, and the width of the thickness distribution was about 700 angstroms.

From these results, it was confirmed that the range of the thickness distribution of the film formed on the silicon wafer can be narrowed, that is, the oxide film thickness can be made uniform, according to the film forming tray and the film forming method using the same of the present invention.

Next, in order to confirm the effect of the tray having the structure in which the contact area between the backup ring and the tray main body is reduced, the following test was performed.

[ test conditions ]

The following tests were carried out: after a silicon wafer was placed on a tray, the silicon wafer was heated while supplying a source gas to the silicon wafer, and an oxide film (SiO) was formed on the silicon wafer by a CVD method under normal pressure₂) And then the thickness of the oxide film was measured. In this test, a silicon wafer having a diameter of 300mm was tested by a continuous atmospheric pressure CVD apparatus for forming an oxide film by a CVD method, and a raw material gas was monosilane (SiH)₄) With oxygen (O)₂) The mixed gas of (4) was heated in the CVD apparatus to a temperature of 430 ℃ and the target thickness of the oxide film was 3500 ANGSTROM.

In example 2 of the present invention, as a structure for reducing the contact area between the backup ring and the tray main body, a tray having a structure in which a protruding portion is provided on the tray main body 2 and the backup ring is bridged on the protruding portion 2e as shown in fig. 22 is used. For comparison, in example 3 of the present invention, a tray having no structure as shown in fig. 16, in which the contact area between the backup ring and the tray main body is reduced, was used. The diameters of the backup rings in inventive examples 2 and 3 were all the same size.

In inventive examples 2 and 3, the thickness of the oxide film formed on the silicon wafer was measured by a spectroscopic ellipsometer. Further, measurement of oxide film thickness a multipoint measurement of 121 points including the center of the silicon wafer was performed, averaging was performed according to the distance from the center of the silicon wafer and collated, and comparison with inventive examples 2 and 3 was performed. In this case, the region excluding the outer periphery of the wafer was set to 5 mm.

[ test results ]

Fig. 33 is a diagram showing a thickness distribution of an oxide film formed when a film is formed by a CVD method using a tray having a structure in which a contact area is reduced or a tray having no structure. In FIG. 33, the horizontal axis represents the distance (mm) from the center of the silicon wafer, and the vertical axis represents the ratio (%) of the difference in film thickness from the center of the silicon wafer. Here, the ratio (%) of the difference from the film thickness at the center of the silicon wafer is a ratio of the difference from the film thickness at the center of the silicon wafer (angstrom) to the film thickness at the center of the silicon wafer (angstrom).

From the thickness distribution of the oxide film shown in fig. 33, in inventive example 3, using a film formation tray having no structure for reducing the contact area between the backup ring and the tray main body, the thickness of the oxide film was increased by about 8.6% in the vicinity of the outer periphery of the silicon wafer as compared with the center. On the other hand, in inventive example 2, using the film formation tray having the structure in which the contact area between the backup ring and the tray main body was reduced, the thickness of the oxide film was increased by about 1.1% in the vicinity of the outer periphery of the silicon wafer as compared with the center.

Accordingly, it is understood that the film formation tray of the present invention has a structure in which the contact area between the backup ring and the tray main body is reduced, and thus the increase in the thickness of the oxide film in the vicinity of the outer peripheral portion as compared with the center of the silicon wafer can be reduced, and the thickness distribution of the oxide film formed when the tray is used for film formation by the atmospheric pressure CVD method can be made more uniform.

Industrial applicability

The film forming tray of the present invention is used for film forming on a silicon wafer by an atmospheric pressure CVD method by separating the tray main body from the mounting portion of the support ring for supporting the silicon wafer, and can reduce heat conduction from the mounting portion to the outer peripheral portion of the silicon wafer and make the thickness distribution of the formed oxide film uniform.

Further, if the inclined surface for the placement portion is formed so that the inner circumferential side is close to the surface of the tray main body facing the silicon wafer, the outer circumferential portion of the silicon wafer can be supported when the inclined surface is used for film formation on the silicon wafer by the atmospheric pressure CVD method, and the thickness distribution of the oxide film to be formed can be made uniform without causing contact damage to the non-film formation surface of the silicon wafer.

Further, since the tray has a structure in which the contact area between the backup ring and the tray main body is reduced, heat conduction from the tray main body to the backup ring is reduced, heat conduction from the placement portion to the outer peripheral portion of the silicon wafer can be further reduced, and the thickness distribution of the oxide film formed can be made more uniform.

Further, according to the film formation method of the present invention, by using the film formation tray of the present invention, a film can be formed on a silicon wafer with a more uniform thickness distribution.

Therefore, the film formation tray of the present invention and the film formation method using the same can be suitably used for manufacturing silicon wafers.

Description of the reference numerals

1 tray for film formation

1a placing part

1b lower surface

2 tray main body

2a side

2b inner peripheral surface

2w receiving part

2c upper surface

2d recess

2e convex part

2f groove

2j lower surface

2m drive recess

2p, 2p pin through hole

3 backup ring

3a upper surface

3b outer peripheral surface

3c placing part

3d lower surface of the mounting part

3e pillar part

3f support part (foot)

3g lower surface

3h side wall

4 clamping apparatus

5 silicon wafer

5a film-forming surface

5b outer peripheral portion

5c non-film-forming surface

10 film forming apparatus

11A film formation conveyance path

11 tray driving mechanism for film formation

11a, 11b drive roller

11c drive belt

11m drive lug

12 preheating chamber

12a preheating heater

12s, 13s quartz plate

12k, 13k cover

13 film forming chamber

13b film-forming heater

13A, 13B, 13C showerhead

13 Ba-13 Cf narrow slot nozzle (opening part)

13Aa, 13Ab raw material gas narrow-slot nozzle (narrow-slot nozzle)

13Ac, 13Ad Outlet (Slot nozzle)

13Ae, 13Af gas shield (Slot nozzle)

13f raw material gas supply unit

13g gas discharge part

13h blocking the gas supply

14A load/unload position

14 loading/unloading mechanism

14a support pin

14b support pin driving part

14c conveying part

15A circulation conveying path

15 circulation mechanism

15a descending elevator (descending circulation part)

15b position limiting part (descending circulation part)

15c descending driving part (descending circulation part)

15d horizontal circulation part

15e Elevator for ascending (ascending circulation part)

15f position limiter (ascending cycle)

15g ascending driving part (ascending circulating part)

Claims

1. A film forming apparatus is characterized in that,

comprising:

a plurality of film forming trays on which silicon wafers are mounted;

a film forming tray driving mechanism that continuously conveys the film forming tray on a film forming conveyance path extending in a horizontal direction along a main surface of the film forming tray;

a plurality of gas nozzles for blowing a source gas toward the silicon wafer;

a film-forming heater for heating the film-forming tray;

a loading/unloading mechanism for delivering and receiving the silicon wafer to and from the film formation tray at a loading/unloading position;

a circulating mechanism for circulating the film-forming tray after film formation to the loading/unloading position along a circulating conveying path;

the film forming tray comprises a tray main body and a support ring which is erected on the tray main body and supports the outer circumference position of the silicon wafer, and a carrying part for directly carrying the silicon wafer is arranged on the support ring;

the placing part has a lower surface of the placing part, which is separated from the surface of the tray main body opposite to the silicon wafer placed at a distance;

and the tray main body is made of powder sintered ceramics, the backup ring is cut out from a bulk ceramic grown from a vapor phase,

the tray main body and the backup ring are made of SiC,

the ratio of the heat capacity of the backup ring to the inner diameter of the backup ring, i.e., the heat capacity/inner diameter, is set in the range of 1.2 to 5.5 (J/K)/cm.

2. The film forming apparatus according to claim 1,

the film forming heater is provided at a lower position of the film forming conveyance path, and heats the film forming tray from a lower surface side thereof.

3. The film forming apparatus according to claim 1 or 2,

the gas nozzle is provided at an upper position of the film formation conveyance path.

4. The film forming apparatus according to claim 1,

the loading/unloading mechanism includes support pins capable of supporting the silicon wafer in a state of penetrating the film formation tray and being driven in a vertical direction when the silicon wafer is transferred to and from the film formation tray;

the film forming tray is provided with a pin through hole through which the support pin can pass.

5. The film forming apparatus according to claim 1,

the silicon wafer has a substantially circular contour.

6. The film forming apparatus according to claim 1,

the source gas supplied to the showerhead includes at least a silicon-containing gas and an oxygen-containing gas.

7. A film forming tray which is continuously conveyed in a film forming conveying path and is used in a film forming apparatus for forming a film on a silicon wafer mounted thereon by blowing a raw material gas from a plurality of gas nozzles,

a tray body and a support ring which is erected on the tray body and supports the silicon wafer, wherein the support ring is provided with a carrying part for directly carrying the peripheral position of the silicon wafer;

wherein the tray main body is made of powder sintered ceramic, the backup ring is cut out from a bulk ceramic grown from a vapor phase, the tray main body and the backup ring are made of SiC,

8. A film forming tray according to claim 7,

the outline of the tray main body is a rectangular plate shape in plan view.

9. A film forming tray according to claim 7,

the tray body is provided with a pin through hole so that a support pin capable of supporting the silicon wafer can be driven in the vertical direction when the silicon wafer is transferred.

10. A film forming tray according to claim 7,

a recessed receiving portion is formed on the upper surface of the tray main body, and the receiving portion receives the support ring which is formed in a circular shape in plan view in accordance with the plan contour of the silicon wafer.

11. A film forming tray according to claim 7,

the lower surface of the tray main body is provided with a drive recess for receiving a driving force from a film formation tray driving mechanism as a state in which a plurality of films are continuously arranged when the film formation tray is conveyed in the film formation conveying path.

12. A film forming tray according to claim 7,

the thickness of the tray body is set within a range of 5 to 10 mm.

13. A film forming tray according to claim 7,

the arithmetic mean roughness Ra of the surface of the support ring on which the silicon wafer is placed is set to be in the range of 0.01 to 2.0 μm.

14. A film forming tray according to claim 7,

the ratio (outer diameter/inner diameter) of the outer diameter of the backup ring to the inner diameter of the mounting portion is set to be in the range of 1.02 to 1.10.

15. A film forming tray according to claim 7,

the thickness of the support ring from the lower surface to the uppermost surface of the mounting portion is set to be in the range of 0.4 to 1.10 mm.

16. A film forming tray according to claim 7,

the height dimension of the support ring from the upper surface of the mounting portion to the uppermost surface is set in the range of 0.2 to 0.6 mm.

17. A method for manufacturing a film forming tray according to any one of claims 7 to 16, wherein the method comprises the steps of,

the method comprises a step of forming the tray body into a ceramic sintered body of sintered powder and a step of vapor-phase growing a ceramic film on the surface of the sintered body.

18. A method for manufacturing a film forming tray according to any one of claims 7 to 16, wherein the method comprises the steps of,

the method comprises a step of vapor-phase growing a bulk ceramic on a predetermined substrate by the backup ring, and a cutting step of cutting a predetermined portion from the bulk ceramic to form the mounting portion.

19. A film-forming method characterized in that,

a film forming apparatus according to any one of claims 1 to 6, wherein an oxide film is formed on the entire surface of the silicon wafer.