Semiconductor device manufacturing: process – Chemical etching – Vapor phase etching
Reexamination Certificate
1999-03-11
2001-07-03
Mills, Gregory (Department: 1763)
Semiconductor device manufacturing: process
Chemical etching
Vapor phase etching
C118S500000, C118S728000, C156S345420, C361S234000, C279S128000
Reexamination Certificate
active
06255223
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a substrate handling method and apparatus, and an attractive force inspection method and apparatus utilized therewith, used in a state wherein an attractive force is generated between a substrate and a substrate holder when the substrate as an object to be processed is held on the substrate holder where various processing is performed, for example, during plasma processing utilized in thin film formation, micro-fabrication and the like in the manufacture of semiconductor devices, liquid crystal display panels, solar cells and the like.
2. Description of the Related Art
To enhance device functionality, and reduce the processing costs thereof, efforts have been energetically undertaken in recent years to make plasma processing apparatus more accurate and faster, and to handle larger diameter process objects, while reducing damage. Of these, control of substrate temperature to achieve inplane uniformity and precision is required in particular to achieve uniform film quality in a substrate during film growth, and to ensure dimensional precision in the dry etching utilized in micro-fabrication, respectively. Plasma processing apparatuses that make use of either a mechanical clamp or an electrostatic attraction electrode have begun to be used as means for controlling the substrate temperature.
As examples of conventional plasma processing apparatus, there are such type as disclosed in Japanese Laid-open Patent Application No. 63-72877, Japanese Laid-open Patent Application No. 02-7520, Japanese Laid-open Patent Application No. 03-102820, and Japanese Laid-open Patent Application No. 04-100257.
FIG. 2
shows a cross-sectional view of the reaction chamber of a plasma processing apparatus disclosed in Japanese Patent Laid-open No. 04-100257. In this plasma processing apparatus, a vacuum chamber
131
having a gas feeding means
140
, gas inlet
140
a
, and an evacuating mechanism
141
is utilized as the plasma processing reaction chamber. A substrate
132
to be processed is placed on top of an electrostatic attraction electrode
133
provided inside the vacuum chamber
131
, and this substrate
132
is electrostatically attracted by the electrostatic attraction electrode
133
. This electrostatic attraction is performed by applying from a direct current power source
134
a positive voltage and a negative voltage, respectively, to a pair of electrodes inside the electrostatic attraction electrode
133
. In this state, ordinary plasma processing is performed on the substrate
132
by evacuating the inside of the vacuum chamber
131
to achieve a predetermined vacuum state, introducing reactive gases, and applying voltage. Plasma processing involves the generation of a plasma gas inside the vacuum chamber
131
by applying a high-frequency voltage from a high-frequency power source
136
, and includes sputtering for forming a thin film which corresponds to the plasma gas constituents, dry etching for forming a conductive pattern by using the plasma gas to selectively remove in accordance with a photoresist a conductive layer on a semiconductor wafer, and ashing for removing unnecessary photoresist subsequent to dry etching.
Following this type of plasma processing, an electric charge remains in the dielectric layer of the surface of the electrostatic attraction electrode
133
even when the direct current power source
134
is shut off, and in some cases, an electric charge remains in the substrate
132
if it is of dielectric properties. For this reason, the substrate
132
continues to be electrostatically attracted to the electrostatic attraction electrode
133
, and even when pushed upward by a push-up mechanism
139
, the substrate
132
either cannot be released from the electrostatic attraction electrode
133
, or incurs damage.
Accordingly, in this apparatus, when plasma processing is complete, the polarity of the applied voltage from the direct current power source
134
to the electrostatic attraction electrode
133
is reversed by a switching mechanism
135
, thereby canceling the residual electric charge of the electrostatic attraction electrode
133
, following which the substrate
132
is pushed upward and released from the electrostatic attraction electrode
133
by the push-up mechanism
139
so that it can be transported to the next process. Thereafter, ultraviolet rays are irradiated through a piece of quartz glass
138
onto the dielectric layer of the surface of the electrostatic attraction electrode
133
from, for example, a mercury lamp, which is an ultraviolet light source
137
, thereby ultimately removing the residual electric charge on the surface of this dielectric layer in preparation for the next substrate to undergo plasma processing.
Conversely, instead of the above-described charge removal, a charge removing plasma process can also be performed. As an example of this kind of processing, there is a method, in which the residual electric charge is reduced by gradually lowering the applied power.
However, with the system in which charge removal is performed by reversing the polarity of the applied direct current voltage to the electrostatic attraction electrode
133
following plasma processing, it is difficult to remove completely but not excessively the residual electric charge. Consequently, there are cases in which either a residual electric charge remains, or a reverse polarity charge is applied, and the substrate
132
remains electrostatically attracted as-is. In a state such as this, if the substrate
132
is pushed up by the push-up mechanism
139
, there is the danger that the process substrate
132
will be damaged. Further, transport trouble, such as the inability to transport, bad transport attitude, droppage, and improper loading at the next process, can occur when the substrate
132
is transported to the next process, thus lowering reliability.
Conversely, with the charge removing plasma process, because data related to the electrostatic attractive force is not directly monitored, the plasma discharge duration is set to last somewhat longer, causing a drop in throughput efficiency. Moreover, with charge removing plasma processing which is performed inside the vacuum chamber, dust is generated from the vacuum chamber caused by micro-sputtering, and there occurs impurities contamination and dust generation from the electrode material, which also leads to reduced quality and reliability.
Furthermore, the above-described electrostatic attraction between the substrate
132
to be processed and the electrostatic attraction electrode
133
, and the problems associated therewith, are also caused by the plasma gas generated by a plasma generating apparatus inside the vacuum chamber for performing plasma processing on the substrate
132
.
An object of the present invention is to provide a substrate handling method and apparatus, and an attractive force inspection method and apparatus utilized therewith, by which a substrate can be gently pushed up and released at proper timing from a substrate holder in accordance with the residual state of an attractive force generated between the substrate holder and the substrate which is supported and processed on the substrate holder.
SUMMARY OF THE INVENTION
To achieve the above-described object, the substrate handling method of the present invention includes a process of pushing up the substrate thereby releasing the substrate from the substrate holder, wherein, when pushing up and releasing the substrate from the substrate holder, data related to an attractive force generated on the substrate to the substrate holder is detected, and when the attractive force is detected to be greater than a predetermined value, the push-up operation is regulated.
Attractive force occurs, for example, as a result of the substrate holder and the substrate being electrically charged because of plasma processing, or when the substrate is electrostatically attracted to and held on the substrate holder by applying a direct current voltage to the
Haraguchi Hideo
Matsuda Izuru
Yamamoto Shigeyuki
Matsushita Electric - Industrial Co., Ltd.
Mills Gregory
Powell A.
Price and Gess
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