Semiconductor wafer etching method

Details Semiconductor wafer etching method Semiconductor wafer etching method

1998-11-10

2001-06-26

Mills, Gregory (Department: 1763)

Radiation imagery chemistry: process, composition, or product th

Radiation modifying product or process of making

Radiation mask

C216S045000, C216S046000, C216S090000, C438S928000, C134S001300

Reexamination Certificate

active

06251542

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of etching semiconductor wafers.
2. Description of Related Art
A conventional method for etching semiconductor wafers, which is illustrated in
FIG. 6
, involves coating protective resist
35
on pattern surface
39
of semiconductor wafer
34
. Protective film
37
is coated on sections other than those requiring etching on etching surface
38
, and alumina plate
36
is adhered on pattern surface
39
via protective film
37
. Then etching is performed and a thin section (not shown in the Figure) is formed on a diaphragm, etc., of the etching surface
38
.
In the conventional etching method, each manufacturing step represented by process (a) to (f) in
FIG. 7
is performed. First, in protective resist application step (a), protective resist
35
is coated on pattern surface
39
in order to prevent pattern surface
39
of semiconductor wafer
34
from being scratched.
Next, in alumina plate application step (b), alumina plate
36
is heated with a hot plate, etc., and solid petroleum protection wax is heated and melted, and spread over the alumina plate
36
. Then, pattern surface
39
side is directed toward the alumina plate
36
side, and set so that semiconductor wafer
34
is pressed thereon. The melted petroleum protection wax is then applied in the same manner to the circumference of semiconductor wafer
34
.
Etching surface
38
is alkali-etched in etching step (c). When the alkali etching is completed, the semiconductor wafer is reheated with a hot plate, or other type of heating device, in alumina plate removal step (d) in order to remove unnecessary alumina plate
36
.
In wax cleaning step (e), the petroleum protection wax adhered to the semiconductor wafer
34
is cleaned off with trichloroethane. Finally at resist peeling step (f), the protective resist
35
is peeled and cleaned off with a solvent such as FUJI HUNT MS1001 and trichloroethane.
With the above-described conventional semiconductor wafer etching method, as the protective film
37
is formed by heating and melting the petroleum protection wax, which is solid at room temperature, the steps of applying an alumina plate (b) and removing the alumina plate (d) are performed. When the semiconductor wafer
34
is pressed against the alumina plate
36
as the alumina plate
36
is applied thereto in step (b), the roughness of the surface of alumina plate
36
affects pattern surface
39
of the semiconductor wafer
34
, which could result in pattern surface
39
being scratched. Therefore, protective resist
35
must be used in order to prevent scratches. Protective film
37
and protective resist
35
are peeled off and cleaned after etching, but the trichloroethane used as the peeling solvent for both items must have an outstanding cleaning efficiency. Due to the fact that increased attention is being paid to global environmental pollution, and especially as the destruction of the ozone layer is becoming a worldwide problem, the use of trichloroethane has been limited with fluorocarbons as an ozone-destruction organic substance (chlorine solvent), and thus, future use will not be possible.
Therefore, with conventional technology, complete peeling and cleaning of the protective resist
35
and protective film
37
will not be possible.
SUMMARY OF THE INVENTION
This invention aims at accurately etching a semiconductor wafer using a protective film that can be sufficiently peeled and cleaned from the wafer without using restricted solvent such as trichloroethane or fluorocarbons.
To achieve this object, this invention features a protective film formation process that designates the semiconductor wafer's side, first surface, and first portion of a second surface opposite the first surface as non-etched surfaces, and applies and forms an alkali resistant resin or silicon resin protective film on the entire non-etched surface. The etching process then etches a second portion of the second surface after formation of the protective film, and the protective film is peeled from the wafer and the wafer is cleaned. The protective film is peeled using a solvent.
An addition reaction type, deoxime type or deacetone type silicon resin may be used as the protective film coated and formed in the protective film formation process.
According to the present invention, an alkali resistant resin or silicon resin protective film is formed on the sections of the semiconductor wafer that are not etched, and then the designated etching surface (also referred to herein as the specific region) is etched. Thus, only the etching surface is etched. After etching, the protective film is completely separated and cleaned with a solvent other than trichloroethane or fluorocarbons.


REFERENCES:
patent: 3847690 (1974-11-01), Campbell, Jr. et al.
patent: 4304681 (1981-12-01), Martin et al.
patent: 4384919 (1983-05-01), Casey
patent: 5217568 (1993-06-01), Tessier et al.
patent: 5300172 (1994-04-01), Ishiwata et al.
patent: 5324410 (1994-06-01), Kummer et al.
patent: 5397400 (1995-03-01), Matsuno et al.
patent: 5585450 (1996-12-01), Oaks et al.
patent: 5874365 (1999-02-01), Tomita et al.
patent: 59-69933 (1984-04-01), None
patent: 61-002152 (1986-01-01), None
patent: 63-40325 (1988-02-01), None
patent: 63-246820 (1988-10-01), None
patent: 63-313159 (1988-12-01), None
patent: 1-145816 (1989-06-01), None
patent: 3-25235 (1991-03-01), None
patent: 3-41935 (1991-04-01), None
patent: 3-56132 (1991-05-01), None
patent: 3-124450 (1991-05-01), None
patent: 3-212811 (1991-09-01), None
patent: 4-291921 (1992-10-01), None
patent: 5-33527 (1993-04-01), None
patent: 7-249563 (1995-09-01), None
patent: 8-062631 (1996-03-01), None
“Integrated Circuit Fabrication Technology”, David Elliott; ©1989; McGraw-Hill; pp. 407-413.

Affiliated with

Also associated with

Rating

Semiconductor wafer etching method does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Semiconductor wafer etching method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor wafer etching method will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2443688