Wafer holder

Details Wafer holder Wafer holder

2000-06-08

2001-09-11

Hail, III, Joseph J. (Department: 3723)

Work holders

Holder encloses work

C269S021000, C269S903000, C451S365000, C451S364000

Reexamination Certificate

active

06286825

ABSTRACT:

BOTTOMGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wafer holder. More particularly, the present invention relates to an improved wafer holder that not only fixes a wafer while one surface of the wafer is processed but also effectively protects another surface of the wafer at the same time.
2. Description of the Prior Art
In a contemporary semiconductor fabricating process, a wafer holder not only is used to load/unload a wafer to/from a processing chamber and for stably holding and supporting the wafer during a wafer transfer process, but also is used to fix a wafer in/on a processing chamber as the wafer is processed by this processing chamber. Obviously, different types of wafer holders are required by different process, and new type of wafer holder is required as new process is available.
For example, for most of conventional semiconductor devices, only the frontside of wafer where chips locate on is processed and then the backside of wafer can be slightly damaged with any disadvantage about corresponding semiconductor devices. Thus, wafer holder can directly touch the backside of wafer because it is not necessary to protect the backside. However, for some specific semiconductor devices such as power metal oxide semiconductor transistor, not only the frontside of wafer is processed but also the backside is processed, such as forming a metal layer on total backside as chips are formed on frontside. In this way, it is desired to modifying the wafer by a modified wafer holder that can properly protect total surfaces, frontside and backside, of the wafer.
FIG. 1
qualitatively illustrates a conventional wafer holder that adapted in a chamber, such as chamber for E-beam deposition, and is used to fix a wafer in/on wall of the chamber. However, no wafer is available in FIG.
1
. The conventional wafer holder includes wafer support section
11
which has hole
12
for locating a wafer, and both wafer clamp
13
and one or more fastening devices for fastening wafer on/in wafer support section
11
. Herein, each fastening device having a
11
fixed terminal
14
locates on wafer support section
11
and a movable terminal
15
that can be used to fasten the wafer. Further, wafer support section
11
can be part of wall of the chamber.
FIG. 2
is fractional cross-sectional illustration about relation between conventional wafer holder and wafer, herein a wafer is held by the conventional wafer holder. As shown in
FIG. 2
, as wafer
16
is fastened by the conventional wafer holder, movable terminals
15
directly touch wafer
16
. Thus, as both surfaces of wafer
16
is required to be processed, movable terminals
15
will induce some mechanical damages on surface of wafer
16
. For example, if it is necessary to form a metal layer on the back surface of wafer
16
after chips
17
on frontside are fabricated, movable terminals
15
will damage these chips as backside of wafer
16
faces to inner of chamber and wafer
16
is fastened by wafer clamp
13
and fastening devices. Moreover, even only wafer clamp
13
is used and fastening devices are omitted, the truth that wafer
16
is unshaded still is an unavoidable disadvantage of conventional wafer holder: whenever pollution occurs, such as reveal as of depositing process, surface of wafer
16
will be chemically damaged. For example, when backside of wafer
16
is processed, chips on frontside of wafer
16
will be damaged as unexpected pollution is occurred.
Therefore, it is significantly that conventional wafer holder can not properly protect both surfaces of wafer from mechanical/chemical damage, and then it is desired to develop a new wafer holder for properly protecting both surfaces of wafer.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a wafer holder which overcomes the problems encountered in the conventional wafer holder.
It is another object of the present invention to provide an improved wafer holder that more effectively protects the wafer under processed and prevents formalized chips on the wafer is damaged.
To achieve the above objects, this invention provides a wafer holder which includes a wafer support section having a hole for locating a wafer; a cover covering wafer, wherein any chip of the frontside of wafer is not touched with cover, and one or more fastening devices for fastening cover on wafer support section, each fastening devices having a fixed terminal and a movable terminal where fixed terminal locates on wafer support section and movable terminal pressed cover on wafer support section.
In addition, the wafer holder may further comprise a bearing structure, such as wafer clamp, which is used to bear the wafer and usually abutting the hole. However, the wafer support section can be part of wall of chamber where the wafer is processed, and then the wafer support section may be an optional element of the present invention.
Additional advantages, objects and other features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.


REFERENCES:
patent: 5280894 (1994-01-01), Witcraft et al.
patent: 5589003 (1996-12-01), Zhao et al.
patent: 5853169 (1998-12-01), Hern et al.
patent: 5975183 (2000-11-01), Reis et al.
patent: 6068547 (2000-05-01), Lupi
patent: 6164633 (2000-12-01), Mulligan et al.

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