Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – With gas inlet structure
Reexamination Certificate
2002-04-30
2004-12-28
Hassanzadeh, Parviz (Department: 1763)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
With gas inlet structure
C156S345350, C118S7230ME
Reexamination Certificate
active
06835277
ABSTRACT:
The present application claims priority under 35 U.S.C. §119 to Korean Application No. 2001-34100 filed on Jun. 16, 2001, which is hereby incorporated by reference in its entirety for all purposes.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ashing apparatus for a semiconductor device, and more particularly, to an ashing apparatus by which ionized gases are poured into a chamber provided in a dry etching equipment and are uniformly diffused on wafers through ring-shaped pipes.
2. Description of the Related Art
Generally, semiconductor devices can be fabricated by combination of a great number of processes such as the formation of a thin film on a wafer, patterning of a thin film, a washing process, and the like. A process in which a photoresist remaining on a wafer after an etch process is removed is called an ashing process. The ashing process may be called a P/R strip process, which is a type of dry etch process.
In a common dry etching process, gases poured into a reaction chamber are changed into a plasma state by an electrical action such as a discharge, and wafers are etched by the plasma. In contrast, in an ashing process, ionized plasma only is selected from the whole plasma of reactive gases and ashing is performed by the ionized plasma, i.e., ion components. In such an ashing process, the ion components are created outside of a reaction chamber, and are guided into the internal portion of the chamber. An ashing process can be classified into multi-type and single-type ashing processes, according to the way the wafers are arranged to be processed in a chamber. The multi-type ashing process commonly includes accumulating and processing the wafers in batches.
FIG. 1
illustrates a conventional single-type process ashing apparatus, which will be briefly.explained as follows. In the single-type process semiconductor ashing apparatus, ions are injected into the reaction chamber
10
through an ion inlet (ion ejector)
11
, as shown in FIG.
1
. Such an injection method is similar to the method in a multi-type process ashing apparatus, by which ions are created outside of the chamber and are injected into the chamber. That is, the ion inlet (ion ejector)
11
serves to guide only ion components out of plasma made in plasma quartz PQ, into chamber
10
. The plasma is generated in the quartz that is placed outside of the chamber by a radio frequency power source (RF power source). The ions introduced into the chamber
10
flow through a gas diffuser plate
20
(GDP) which is formed with numerous through holes
21
and which serves to divide the internal space of the chamber into two spaces, i.e., the upper and lower spaces.
The GDP
20
is commonly made of quartz. The ions that pass through the GDP
20
are sprayed on a wafer
30
that is placed on the stage
40
in a lower side or space of the chamber
10
. That is, the ions are injected into the reaction chamber
10
through the ion ejector
11
, and the ions that pass through the ion ejector
11
are again passed through the GDP
20
, thereby being sprayed on a wafer
30
. At this time, the ions are uniformly sprayed on the wafer
30
due to the uniformly formed through holes
21
.
The reason that the ion ejector
11
is formed at a sidewall of the chamber will be briefly explained as follows. In an ashing process, photoresist on a wafer should be in a softened state, so that ions properly react with the photoresist as well as the wafer. A hardened photoresist on the wafer will react weakly with ions, so that ashing cannot be effectively performed. Therefore, in order to make the photoresist soft, it is necessary to heat the photoresist at a predetermined temperature. To heat only the photoresist without affecting any other adjacent objects, a halogen lamp (not shown) is employed to heat the photoresist. The halogen lamp radiates light and the light serves to heat the photoresist on the wafer in the chamber. That is, the light radiated from the halogen lamp passes through the upper cover
12
formed of quartz and illuminates the inside of the chamber
10
. The light is also radiated onto the wafer
30
after passing through the GDP
20
, which is also made of quartz. As a result, the light serves to heat the photoresist on the wafer
30
due to the heat energy of the light, thereby softening the photoresist.
In such an environment, in order for the wafer to be directly contacted with the light radiated from the halogen lamp that is provided over the cover
12
, intervening objects cannot be provided between the cover
12
and the wafer
30
. For this reason, the ion ejector
11
through which the ions are passed should be formed at the sidewall of chamber
10
, as shown in FIG.
1
. However, there is a problem in such an apparatus in that since ions are injected into chamber
10
through ion ejector
11
provided at a sidewall of chamber
10
, the portion of GDP
20
adjacent to the ion ejector
11
is provided with a relatively greater number of ions than a portion of GDP
20
that is placed far from the ion ejector
11
. The ions passed through GDP
20
in such an environment cannot be uniformly distributed on a wafer.
In other words, a portion of wafer
30
nearer to the ion ejector
11
is provided with a relatively large amount of ions, as illustrated in FIG.
2
. However, a portion of wafer
30
that is placed far from the ion ejector
11
is provided with a relatively small amount of ions. As a result, the distribution of ions on the wafer is not uniform, thereby causing the problem that ashing efficiency of a wafer decreases.
Particularly, there is also a problem that since the light radiated from the halogen lamp is transmitted both through the upper cover
12
made of quartz and the GDP
20
made of quartz, the transmissivity of light decreases. As a result, the heating rate of the photoresist by the transmitted light in chamber
10
accordingly decreases.
SUMMARY OF THE INVENTION
The present invention is therefore directed to an ashing apparatus which substantially overcomes one or more of the problems due to the limitations and disadvantages of the related art.
To solve the above noted problems, it is an object of the present invention to provide an ashing apparatus by which ions can be uniformly sprayed onto a wafer in a chamber through a ring shaped distribution pipe, thereby increasing ashing uniformity of a wafer.
It is another object of the present invention to provide an ashing apparatus in which light radiated from a halogen lamp can be transmitted through an upper cover only, to directly illuminate a wafer, thereby increasing heating efficiency and raising ashing efficiency of a wafer.
In order to achieve these objects, there is provided an ashing apparatus which includes a chamber; a plasma quartz in which plasma ions are generated; an inlet provided at a sidewall of the chamber through which the plasma ions are ejected into the chamber; a chamber upper cover made of quartz, through which light radiated from a halogen lamp is transmitted for ashing a wafer by heat of the light; and a ring shaped distribution pipe, coupled to the inlet and disposed along a circumference of an interior of the chamber, the ring shaped distribution pipe having a plurality of distribution holes through which the ions are directly sprayed onto the wafer.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 4687544 (1987-08-01), Bersin
patent: 5226056 (1993-07-01), Kikuchi et al.
patent: 6013155 (2000-01-01), McMillin et al.
patent: 6132552 (2000-10-01), Donohoe et al.
patent: 58184724 (1983-10-01), None
patent: 08124909 (1996-05-01), None
Hassanzadeh Parviz
Samsung Electronics Co,. Ltd.
Volentine Francos & Whitt PLLC
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