JP3649265B2 - Thin film vapor deposition equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention particularly relates to a thin film vapor phase growth apparatus for vapor phase growing a high dielectric or ferroelectric thin film such as barium titanate / strontium on a substrate.
[0002]
[Prior art]
In recent years, the degree of integration of integrated circuits in the semiconductor industry has been remarkably improved, and research and development of DRAMs with a gigabit order in the future from the current megabit order has been conducted. In order to manufacture such a DRAM, a capacitor element capable of obtaining a large capacity in a small area is required. As a dielectric thin film used for manufacturing such a large-capacity element, a tantalum pentoxide (Ta ₂ O ₅ ) thin film having a dielectric constant of about 20 instead of a silicon oxide film or a silicon nitride film having a dielectric constant of 10 or less. Alternatively, metal oxide thin film materials such as barium titanate (BaTiO ₃ ) having a dielectric constant of about 300, strontium titanate (SrTiO ₃ ), or a mixture thereof, such as barium strontium titanate, are promising.
[0003]
When vapor-depositing such a metal oxide thin film on a substrate, the substrate is placed on a susceptor (heating holding unit) arranged in an airtight film forming chamber and is built in the susceptor. A thin film in which a mixed gas of a source gas and a reactive gas (oxygen-containing gas) is jetted toward the substrate W from a shower head installed in the film forming chamber while the substrate is heated to a predetermined temperature by a heating means such as a heater. A vapor phase growth apparatus is used.
[0004]
[Problems to be solved by the invention]
By the way, as a characteristic of the film forming raw material as described above, the vapor phase maintenance temperature range after vaporization is narrow, and it is condensed when it falls below the vaporization temperature and decomposes when it rises. On the other hand, the inventors have proposed a method of forming a film while maintaining and controlling the inner wall surface of the reaction chamber at a predetermined temperature (substantially vaporization temperature) (Japanese Patent Laid-Open No. 9-2896). It was found that the generation of objects can be effectively suppressed, but it cannot be completely reduced to zero, and a small amount of fine products are generated and adhered.
[0005]
Therefore, as a result of performing a thermal analysis on the raw material, there is no clear and complete temperature range in which three kinds of liquid raw materials such as BST / SBT can simultaneously maintain a gas phase state, and some of the raw materials are condensed or It turns out that it breaks down. It was also found that the decomposed raw material is difficult to clean, while the condensed raw material is relatively easy to clean. Therefore, a practical solution to the above problem has been made by adopting a method that avoids decomposition at high temperatures while allowing partial condensation.
[0006]
In view of the above, the present invention provides a thin-film vapor phase growth apparatus capable of stably performing uniform and high-quality film formation processing on a substrate while avoiding decomposition of a film formation raw material at a high temperature on a wall surface in a film formation chamber. The purpose is to provide.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, a holding heating unit that holds and heats the substrate in a generally cylindrical airtight film forming chamber, and the holding heating unit is moved up and down at least between the film forming position and the transfer position. Elevating mechanism, gas injection head for injecting a film forming source gas from the top of the film formation chamber toward the substrate, a substrate transfer port opened to a height corresponding to the transfer position on the side wall of the film formation chamber, and film formation in the thin-film vapor deposition apparatus in which an opening for the exhaust port and is provided at a height between said film forming position and transport position of the side wall of the chamber, the exhaust gas enclose take around the substrate holding heating means at the film formation position A substantially cylindrical heat insulating member that forms a part of the flow path is provided, and the heat insulating member is provided with a flow path through which a heat medium is circulated. A temperature control means for controlling to a predetermined temperature is provided, and the heat insulating member is It is a thin film vapor deposition apparatus according to claim is provided detachably in KiNarumaku chamber.
[0008]
Thereby, the heat insulating member suppresses the radiation of heat from the holding heating means, and the inner wall of the film forming chamber is prevented from being heated above the decomposition temperature of the raw material. Therefore, the raw material is prevented from being decomposed and attached at these locations. When the raw material condenses in these places, it is washed and removed by a predetermined method, and the operation of the apparatus is continued. The heat insulating member is preferably formed of a heat insulating material such as quartz, stainless steel, or ceramics.
[0009]
Here, the temperature control means includes, for example, a medium flow path formed in the heat insulating member and a heat medium supply means for supplying a medium controlled to a predetermined temperature outside.
[0010]
The invention described in 請 Motomeko 2 is a thin-film vapor deposition apparatus according to 請 Motomeko 1 you further comprising a cooling means for cooling the outer wall of the deposition chamber to below a predetermined temperature. A support member for supporting the heat insulating member may be provided in the film formation chamber below the exhaust port and above the transfer port.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a first embodiment of the present invention. This thin-film vapor phase growth apparatus holds a substrate W in a substantially cylindrical airtight film forming chamber 10 and heats the substrate W. Means 12, a raising / lowering mechanism 14 for raising and lowering the substrate holding and heating means 12 at least between a film forming position (upper limit) and a transfer position (lower limit), and a film forming source gas from the top of the film forming chamber 10 toward the substrate W Between the film forming position and the transfer position of the side wall 18 of the film forming chamber 10, the substrate transfer port 20 opened to a height corresponding to the transfer position of the side wall 18 of the film forming chamber 10, An exhaust port 22 that opens to a height is provided. One exhaust port 22 and one substrate transport port 20 are provided at predetermined positions in the circumferential direction.
[0012]
The substrate holding / heating means 12 includes a disk-shaped susceptor 24 having a heater (heating means, not shown) therein, and a column 26 for connecting the susceptor 24 to the elevating mechanism 14. At the outer edge of the substrate of the susceptor 24, an annular deposition preventing plate 28 for preventing adhesion due to reaction here is attached. The gas injection head 16 has a nozzle plate 32 having a disk shape slightly larger than the substrate W and in which a plurality of nozzle holes 30 are evenly distributed, and in this example, a raw material gas and a reactive gas (for example, an oxidizing gas) are contained therein. ) And a jacket (temperature control means) 34 for maintaining the nozzle hole 30 and the mixing space at a predetermined temperature with a heat medium.
[0013]
The film forming chamber 10 includes a cylindrical side wall 18, a bottom plate 36 in which an opening for attaching the substrate lifting mechanism 14 is formed at the center, a gas jet head 16 that also serves as a top plate, and a tapered portion between the side wall 18 and the head. The O-ring 40 and the bellows 42, which are seal members, are disposed at necessary portions, and the transfer port 20 is provided with a gate (not shown). In this example, the side wall 18 and the bottom plate 36 are not formed with a heat medium flow path as temperature control means.
[0014]
In the film forming chamber 10, a cylindrical heat insulating member 44 is provided so as to surround the elevating path of the substrate holding heating means 12. The heat insulating member is integrally formed with an annular plate 46 that is protruded and attached to the lower part of the heat insulating material such as quartz, stainless steel, or ceramics. The inner surface of the side wall 18 of the film forming chamber 10 is mounted on an annular protrusion 48 formed at a position below the exhaust port and above the transfer port. Therefore, by removing the top shower head 16 and the taper block 38, they can be lifted and removed from the film forming chamber 10 or exchanged easily.
[0015]
The operation of the thin film vapor phase growth apparatus configured as described above will be described. The susceptor 24, at the transfer position indicated by the two-dot chain line in FIG. 1, this position the substrate W from the substrate transfer port 20 is raised to the deposition position shown in Figure 1 by the lifting mechanism 14. The substrate W is heated to the film forming temperature by the susceptor 24, and a mixed gas of the source gas and the reactive gas is sprayed from the shower head 16 maintained at a predetermined temperature by the heat medium.
[0016]
The injected source gas and the reactive gas react to form a film on the substrate W, and the reacted gas flows radially on the substrate W and is formed by the side wall 18 of the film forming chamber 10 and the heat insulating member 44. It flows into P and is exhausted from the exhaust port 22. Here, the flow path of the reaction gas is limited by the heat insulating member 44 and the annular plate 46 and is difficult to flow to the back side of the susceptor 24, the elevating mechanism 14 below the film forming chamber 10, and the like. Contamination and the like resulting from it are prevented.
[0017]
During the film formation reaction, the heat insulating member 44 suppresses the radiation of heat from the holding heating means 12 and prevents the side walls 18 and the like of the film formation chamber 10 from being heated above the decomposition temperature of the raw material. Therefore, the raw material is prevented from being decomposed and attached at these locations. When the raw material condenses in these places, the shower head 16 and the taper block 38 at the top of the film forming chamber 10 are removed, and these places are removed by cleaning by a predetermined method, and the operation of the apparatus is continued. .
[0018]
FIG. 2 shows a thin film vapor phase growth apparatus according to a second embodiment of the present invention. In this embodiment, the heat insulating member 44 has a simple cylindrical shape and is detachably attached to the annular groove 52 of the support plate 50 provided on the inner surface of the side wall 18 of the film forming chamber 10. In this embodiment, since the shape is simple and compact, not only the heat insulating member 44 is easily manufactured, but also removal and replacement are further facilitated. In particular, it is convenient when changing the material of the heat insulating member 44 according to the film forming conditions.
[0019]
FIG. 3 shows another embodiment of the present invention, in which a flow path 54 through which a heat medium such as oil flows is formed inside the heat insulating member 44. This is provided with a heat medium supply pipe 56 and a return pipe which are inserted through the side wall 18 of the film forming chamber 10 and supply a heat medium having a predetermined temperature from an external supply means. In this embodiment, since the radiant heat received from the heat holding member is absorbed by the heat medium, the function of suppressing the temperature rise of the side wall 18 of the film forming chamber 10 is higher.
[0020]
FIG. 4 shows still another embodiment of the present invention. Here, in order to prevent the side wall 18 and the elevating flange 60 from being heated by the holding heating means 12 as much as possible, the cooling means is configured. A jacket 59 is also formed on the jacket 58 of the side wall 18 and the elevating flange 60 fixed to the bottom plate 36. Thereby, in addition to the heat shielding function of the heat insulating member 44, the function of more reliably maintaining the temperature of the inner wall of the film forming chamber 10 below the film forming reaction is ensured. Furthermore, it contributes to the improvement of the durability of the sealing parts and the safety of workers.
[0021]
【The invention's effect】
As described above, according to the present invention, the heat insulating member suppresses heat radiation from the holding and heating means, and the inner wall of the film forming chamber is prevented from being heated above the decomposition temperature of the raw material. Therefore, it is possible to prevent the raw material from being decomposed and adhered at these places, and to perform a uniform and high quality film forming process on the substrate stably.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a thin film vapor phase growth apparatus according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a thin film vapor phase growth apparatus according to a second embodiment of the present invention.
FIG. 3 is a sectional view showing a thin film vapor phase growth apparatus according to a third embodiment of the present invention.
FIG. 4 is a sectional view showing a thin film vapor phase growth apparatus according to a fourth embodiment of the present invention.
[Explanation of symbols]
10 Deposition chamber 12 Susceptor (Substrate holding and heating means)
14 Lifting mechanism 16 Gas injection head 18 Side wall 20 Substrate transport port 22 Exhaust port 30 Injection nozzle 32 Nozzle panel 44 Heat insulation member 59 Jacket 60 Lifting flange P Flow path M Mixing space W Substrate

Claims (2)

A holding heating means for holding and heating the substrate in a substantially cylindrical airtight film forming chamber, a lifting mechanism for raising and lowering the holding heating means at least between the film forming position and the transfer position, and the top of the film forming chamber A gas injection head for injecting a film forming raw material gas toward the substrate, a substrate transfer port opened to a height corresponding to the transfer position on the side wall of the film forming chamber, and the film forming position on the side wall of the film forming chamber. In the thin film vapor phase growth apparatus provided with an exhaust port opening at a height between the transfer positions,
Substantially cylindrical insulating member which forms a part of the flow path of the exhaust gas enclose take around the substrate holding heating means at the film formation position is provided,
The heat insulating member is formed with a flow path through which a heat medium flows, and is provided with temperature control means for controlling itself to a predetermined temperature by supplying the heat medium from the outside.
The thin-film vapor phase growth apparatus , wherein the heat insulating member is detachably provided in the film forming chamber . Thin film vapor deposition apparatus according to 請 Motomeko 1 further comprising a cooling means for cooling the outer wall of the deposition chamber to below a predetermined temperature.

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