Coating apparatus – Gas or vapor deposition – Work support
Reexamination Certificate
1998-12-17
2001-02-27
Bueker, Richard (Department: 1763)
Coating apparatus
Gas or vapor deposition
Work support
Reexamination Certificate
active
06193803
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor holding apparatus for holding a semiconductor substrate in semiconductor processing equipment and, more particularly, to a structure of a susceptor for holding a substrate in plasma CVD equipment.
2. Description of the Related Art
Plasma CVD equipment is commonly used for exciting a particular source gas in an evacuated reaction chamber using high-frequency plasma to deposit a thin film on a semiconductor substrate. Reaction products similar to those on the surface of a semiconductor wafer are deposited on the inner wall of the reaction chamber of such plasma CVD equipment. It is therefore necessary to perform plasma etching periodically using a gas including fluorine atoms to eliminate the reaction products for cleaning in order to prevent contamination of a semiconductor wafer. In doing this, a susceptor is required above all to be resistant to fluorine so that it does not react with fluorine active species to generate a contaminant. Since it is also required to heat a semiconductor substrate rapidly to a predetermined temperature, high thermal conductivity is also required.
Anodized susceptors made of aluminum or aluminum alloy incorporating a high-frequency electrode have been widely used as substrate holding apparatuses for holding a substrate in plasma CVD equipment. However, a problem has existed in that the surface of an anodized susceptor is liable to cracks in a plasmatic environment at 400° C. and in that fluorine active species penetrate into the cracks to corrode aluminum inside.
Under such circumstances, susceptor devices such as that disclosed in U.S. Pat. No. 5,558,717 have been developed which have a structure wherein a mount plate made of aluminum nitride for mounting a semiconductor substrate is put in contact with an upper surface of a heating block made of high purity aluminum with a nichrome wire embedded therein. Such conventional susceptors were developed to take advantage of the fact that ceramic materials such as aluminum nitride are resistant to fluorine based active species and are excellent in thermal conductivity.
However, such conventional susceptors face a difficulty in mechanically attaching and fixing their components due to distortions attributable to the fact that two types of materials, i.e., aluminum nitride and high purity aluminum, having significantly different thermal expansion coefficients are put in contact with each other. As a result, a problem arises in that there will be imperfect contact regions into which active species of fluorine can penetrate to corrode the top surface of the heating block, thereby generating a contaminant.
Further, the part of the heating block of such conventional susceptors can react with fluorine active species to generate a contaminant because it is made of aluminum.
Since the susceptors also serve as high-frequency electrodes, such imperfect contact can produce a parasitic capacity which can adversely affect the distribution of high-frequency discharge.
Furthermore, the conventional susceptors have a problem in that their manufacturing cost is high and the operating cost of an apparatus is therefore increased.
It is therefore an object of the invention to provide a substrate holding apparatus having a mount surface which is highly resistant to fluorine based active species and free from the risk of contamination by impurities.
It is another object of the invention to attach a mount plate and a heating block to each other with perfect tightness to eliminate any gap through which fluorine active species can enter, thereby improving resistance to fluorine and improving thermal conductivity to improve process stability.
It is still another object of the invention to shield a heating block from fluorine active species completely, thereby improving the resistance of a substrate holding apparatus as a whole to fluorine active species.
It is a further object of the invention to provide a substrate holding apparatus at a low cost, thereby reducing the apparatus operating cost.
SUMMARY OF THE INVENTION
In order to achieve the above-mentioned objects, a substrate holding apparatus according to the invention comprises means as described below.
A substrate holding apparatus according to the invention for holding a semiconductor substrate inside a semiconductor processing equipment comprises:
a mount plate made of an aluminum alloy wrought products and having a mount surface for use in mounting the semiconductor substrate thereon;
a heating block with a heater body being embedded therein for heating the semiconductor substrate; and
a shield member made of an aluminum alloy wrought products for use in housing therein the heating block,
wherein the top surface of the heating block is tightly attached to the bottom surface of the mount plate.
The heating block is preferably made of aluminum alloy.
The tight attachment is specifically achieved by brazing the bottom surface of the mount plate and the top surface of the heating block.
The tight attachment is also achieved by fixing the mount plate and the heating block together at least one bolt.
Alternatively, a substrate holding apparatus according to the invention for holding a semiconductor substrate inside a semiconductor processing equipment comprises:
a mount plate made of an aluminum alloy wrought products and having a mount surface for use in mounting the semiconductor substrate thereon;
a heating block with a heater body embedded therein for heating the semiconductor substrate;
an auxiliary plate made of an aluminum alloy wrought products, the auxiliary plate being inserted between the mount plate and the heating block; and
a shield member made of an aluminum alloy wrought products for use in housing therein the heating block,
wherein the top surface and bottom surface of the auxiliary plate are tightly attached to the bottom surface of the mount plate and the top surface of the heating block, respectively.
Preferably, the heating block is made of aluminum alloy.
The tight attachment between the top surface of the auxiliary plate and the bottom surface of the mount plate is specifically achieved by fixing the auxiliary plate and the mount plate together by using at least one bolt.
The tight attachment between the bottom surface of the auxiliary plate and the top surface of the heating block is specifically achieved by brazing together the bottom surface of the auxiliary plate and the top surface of the heating block.
Further alternatively, a substrate holding apparatus according to the invention for holding a semiconductor substrate in semiconductor processing equipment comprises:
a mount plate made of a ceramic material and having a mount surface for use in mounting the semiconductor substrate thereon;
a heating block with a heater body embedded therein for heating the semiconductor substrate;
an auxiliary plate made of an aluminum alloy wrought products, the auxiliary plate being inserted between the mount plate and the heating block; and
a shield member made of an aluminum alloy wrought products for housing therein the heating block,
wherein the top surface and bottom surface of the auxiliary plate are tightly attached to the bottom surface of the mount plate and the top surface of the heating block, respectively.
The ceramic material is specifically any of aluminum nitride, alumina or magnesium oxide.
The tight attachment between the top surface of the auxiliary plate and the bottom surface of the mount plate is specifically achieved by fixing together the auxiliary plate and the mount plate using at least with one bolt.
The tight attachment between the bottom surface of the auxiliary plate and the top surface of the heating block is specifically achieved by brazing together the bottom surface of the auxiliary plate and the top surface of the heating block.
REFERENCES:
patent: 5558717 (1996-09-01), Zhao et al.
patent: 5968273 (1999-10-01), Kadomura et al.
patent: 6024827 (1999-10-01), Ishii
Mori Yukihiro
Sato Kiyoshi
Shimizu Mikio
ASM Japan K.K.
Bueker Richard
Fieler Erin
Knobbe Martens Olson & Bear LLP
LandOfFree
Substrate holding apparatus for processing semiconductors does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Substrate holding apparatus for processing semiconductors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Substrate holding apparatus for processing semiconductors will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2587659