Coating apparatus – Gas or vapor deposition
Reexamination Certificate
1998-12-15
2001-02-20
Lund, Jeffrie R. (Department: 1734)
Coating apparatus
Gas or vapor deposition
Reexamination Certificate
active
06190459
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gas treatment apparatus for gelatinizing a coated film coated on the front surface of a substrate and forming an insulation film, the coated film being formed by dispersing particles or colloid of a start substance of a film component to solvent.
2. Description of the Related Art
As methods for forming an inter-layer insulation film of a semiconductor device, CVD method, heat oxidizing method, and so forth are known. In addition, sol-gel method is known. In the sol-gel method, a coating solution of which colloid of TEOS (tetraethoxysilane: Si(C
2
H
5
O)
4
) is dispersed to organic solvent such as ethanol solution is coated on the front surface of a semiconductor wafer (hereinafter simply referred to as wafer). The coated film is gelatinized and dried. Thus, a silicon oxide film is obtained. An example of such a method has been disclosed in Japanese Patent Laid-Open Publication Nos. 8-162450 and 8-59362.
FIGS. 9A
,
9
B, and
9
C show degeneration of a coated film in such a method.
When a coating solution is coated on a wafer, particles or colloid
100
of TEOS is dispersed to solvent
200
(refer to FIG.
9
A). Thereafter, the coated film is exposed to alkaline atmosphere or heated. Thus, since TEOS is polycondensated and hydrolyzed, the coated film is gelatinized and thereby a mesh structure of TEOS
300
is formed (refer to FIG.
9
B). The solvent of the coated film is substituted with another solvent
400
such as acetone so as to remove moisture from the coating solution (refer to FIG.
9
C). The solvent substituting treatment is a hydrophobic treatment for the film. In other words, since an OH radical tends to absorb moisture, when the film is reacted with for example HMDS, the OH radical bound to an edge portion of Si—O coupling is substituted with another organic substance.
After the coating solution is dried, a coated film of silicon oxide film is obtained. Moreover, in the solvent substituting treatment shown in
FIG. 9C
, solvent whose surface tension is smaller than that of ethanol is used. Thus, when the solvent vaporizes, since large stress is not applied to the mesh structure of TEOS, the film can be prevented from breaking.
The silicon oxide film formed by the sol-gel method has many air pores. Thus, the dielectric constant ∈ of the oxide film is very close to that of vacuum. Consequently, the electric resistance of the oxide film having air pores is as high as that of vacuum. As a result, an ideal insulation film can be obtained.
When the sol-gel method is applied to a real production line, a coating unit that coats a coating solution to a wafer, an aging unit that contacts ammonium gas to the wafer or heats the wafer at a predetermined temperature (for example, around 100° C.) and gelatinizes the coated film, and a substituting unit that substitutes the solvent of the coated film with another solvent are required.
In the gelatinizing treatment performed by the inventor of the present invention, as shown in
FIG. 10
, a wafer W is placed on a plate
61
. A cylindrical lid
62
is placed on the plate
61
. Thus, a sealing vessel
6
is formed. Ammonium gas is supplied from a gas supplying path
63
on the periphery of the plate
61
. The ammonium gas is exhausted from an exhausting path
64
at the center of the lid
62
.
SUMMARY OF THE INVENTION
In the unit shown in
FIG. 10
, the ammonium gas tends to upwardly flow from the gas supplying opening of the plate
61
along the inner periphery of the lid
62
upwardly. In addition, the ammonium gas is attracted by attracting force of the exhausting path
64
at the center of the lid
61
. Thus, a gas flow takes place in an upper diagonal direction. Since gas that upwardly flows along the inner periphery of the lid
62
becomes a vortex flow at upper corners of the lid
62
, the gas does not smoothly lower. Thus, the gas flow rate and gas concentration at the center portion of the wafer W are smaller than those at the peripheral portion thereof. Consequently, the coated film is unevenly gelatinized and thereby an unsmooth film is formed.
A first aspect of the present invention is made from the above-described point of view.
An object of the first aspect of the present invention is to provide a coated film treatment apparatus that allows a substrate (for example, a wafer) to be treated with an equal gas flow in a sealing vessel so as to obtain a high-quality thin film (for example, an inter-layer insulation film).
A first aspect of the present invention is a gas treatment apparatus, comprising a sealing vessel for treating a substrate with gas, a substrate holding portion, disposed in the sealing vessel, for holding the substrate, a gas flow regulating surface portion, disposed opposite to a treatment surface of the substrate held on the substrate holding portion, the gas flow regulating surface portion protruding to the substrate holding portion and having at least an outer peripheral portion for forming a narrowed gas path with the substrate holding portion, a gas supplying opening disposed along a peripheral portion of the gas flow regulating surface portion, and an exhausting opening facing the treatment surface of the substrate held on the substrate holding portion and disposed at a center portion of the sealing vessel.
The gas treatment apparatus may further comprises a buffer chamber disposed outside the outer peripheral portion and at an upper portion of the gas supplying opening.
An inner periphery of the gas flow regulating surface portion may be composed of a first concave portion formed in almost a spherical surface shape, a convex portion formed inside the first concave portion and protruding in an almost doughnut shape, and a second concave portion formed in an almost circular cone shape inside the convex portion and connected to the exhausting opening wherein the first concave portion, the convex portion, and the second concave portion are inwardly and continuously formed on concentric circles.
The outer peripheral portion may be a partition plate that partitions an inner space of the sealing vessel into a cylindrical space facing the treatment surface of the substrate held on the substrate holding portion and a buffer chamber formed outside the cylindrical space. In addition, an inner periphery of the gas flow regulating surface portion may be composed of an outer portion formed in an almost plane shape, an inclined portion formed inside the outer portion, the inclined portion forming a side surface of an almost circularly cone shaped protrusion portion, a convex portion formed in an almost doughnut shape inside the inclined portion, and a concave portion formed in an almost circularly cone shape inside the convex portion and connected to the exhausting opening wherein the outer portion, the inclined portion, and the convex portion, and the concave portion are inwardly and continuously formed on concentric circles.
An almost spherical surface shaped concave portion may be formed on an inner periphery of the gas flow regulating surface portion.
A circularly cone shaped concave portion with a vertex of the exhausting opening may be formed on an inner periphery of the gas flow regulating surface portion.
The outer peripheral portion may form a partitioning portion with a cylindrical section wherein an inner periphery of the gas flow regulating surface portion is a plane with almost the same height as a vertex portion of the buffer chamber.
An inner periphery of the gas flow regulating surface portion may be composed of a first concave portion formed in almost a spherical surface shape, a convex portion formed inside the first concave portion and protruding in an almost doughnut shape, and a second concave portion formed in an almost circular cone shape inside the convex portion and connected to the exhausting opening wherein the first concave portion, the convex portion, and the second concave portion are inwardly and continuously formed on concentric circles.
The gas supplying opening may be formed in a slit s
Katayama Kyoshige
Mizutani Yoji
Nagashima Shinji
Takeshita Kazuhiro
Lund Jeffrie R.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tokyo Electron Limited
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