Abrading – Abrading process – Utilizing fluent abradant
Reexamination Certificate
2000-03-24
2001-12-25
Hail, III, Joseph J. (Department: 3723)
Abrading
Abrading process
Utilizing fluent abradant
C451S288000, C451S526000, C451S041000
Reexamination Certificate
active
06332830
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a polishing method and a polishing apparatus for polishing (mirror polishing) works (for example, semiconductor wafers or the like), and more specifically to a turn table receiving member supporting a turn table of a polishing apparatus.
BACKGROUND ART
When a work is polished, generally, the polishing is carried out by pressing the work against a polishing pad adhered to a turn table while polishing slurry is flowed on the polishing pad and by rotating the work and the turn table.
A polishing apparatus used for the polishing has a turn table to which a polishing pad is adhered, a turn table receiving member having grooves and supporting the turn table by a grooved surface, a polishing slurry supplying means for supplying polishing slurry to the polishing pad, and a rotating means for rotating a work and the turn table.
Recently, for improving productivity, concretely, for reducing a time of apparatus stop when polishing pads are exchanged, a polishing apparatus in which a turn table is detachable has been used. With the polishing apparatus, while casting, stainless steel and ceramic having high strength are used for materials of the turn table and the turn table receiving member for heightening hardness of the polishing apparatus, grooves are formed in a turn table support surface of the turn table receiving member for easily detaching the turn table from the turn table receiving member.
However, during polishing with the polishing apparatus, the turn table receives a polishing load from the work, while the turn table receives a reaction force from the turn table receiving member. The reaction force becomes contact pressure between the polishing pad and the work. In this case, if grooves are formed in the turn table receiving member, thereby the turn table receives the reaction force from non-groove portions of the turn table receiving member, but does not receive the reaction force from grooved portions. As a result, the contact pressure between the polishing pad and the work becomes non-uniform within a surface of the work, thereby a polishing rate of the work becomes non-uniform within the surface to form minute waviness on the work surface.
With the preceding developed art, as shown in
FIG. 6
, for example, in a case that concentric circle-like grooves
9
d
are provided in a turn table receiving member
3
d
and that a rotation center of the turn table receiving member
3
d
and a rotation center of a work coincide with each other, strong portions and weak portions of contact pressure against a polishing pad generate concentrically and alternately about the rotation center of the work. In this case, the polishing rate of the work changes according to the contact pressure. Thus, with the work, portions corresponding to the non-groove portions are more polished, while portions corresponding to the grooved portions are less polished, thereby, as shown in
FIG. 8
, concentric circle-like waviness is formed on the work W. That is, for example, irregularities of about not more than 0.1 &mgr;m are formed periodically on the work. Such a phenomenon is observed when a pattern of the grooves
9
d
of the turn table receiving member
3
d
is concentric circle-like or spiral.
Further, even if the rotation center of the turn table receiving member and the rotation center of the work do not coincide with each other, that is, the rotation center of the work is eccentric from the rotation center of the turn table receiving member, when concentric circle-like grooves are provided in the turn table receiving member, the contact pressure to the polishing pad in the vicinity of the rotation center of the work becomes either constantly strong or constantly weak, thereby there is a problem that a polishing degree is changed between a central portion of the work and a peripheral portion thereof.
The present invention was developed in view of the above-described problems. An object of the present invention is to provide a polishing method and a polishing apparatus for making contact pressure between a work and a polishing pad substantially uniform within surfaces to obtain a work having good quality.
DISCLOSURE OF THE INVENTION
According to the first aspect of the present invention, a polishing method according to the present invention comprises the steps of supporting a turn table by a grooved surface of a turn table receiving member, the grooved surface being provided with a plurality of grooves in a straight direction, pressing a work against a polishing pad adhered to the turn table while flowing polishing slurry, and carrying out a polishing by rotating the work and the turn table.
According to the polishing method, the plurality of straight line-like grooves are provided in the turn table receiving member, thereby loci of the grooves in the turn table receiving member against respective portions of the rotating work show complex loci, so that the contact pressure between the polishing pad and the work is substantially averaged. Thus, the contact pressure within the surface of the work from the polishing pad is also averaged, thereby a work can be obtained that has good quality.
According to the second aspect of the present invention, a polishing apparatus according to the present invention comprises a turn table to which a polishing pad is adhered, a turn table receiving member supporting the turn table by a grooved surface in which a groove is formed, a polishing slurry supplying unit for supplying polishing slurry to the polishing pad, and a rotating mechanism for rotating a work and the turn table, wherein the groove is provided in the receiving member in a straight direction.
According to the polishing apparatus, a plurality of straight line-like grooves are provided in the turn table receiving member, thereby loci of the grooves in the turn table receiving member against respective portions of the rotating work show complex loci. As a result, the contact pressure of the turn table receiving member is substantially averaged. Thus, the contact pressure within the surface of the work from the polishing pad is also averaged, thereby a work can be obtained that has good quality.
With the polishing method and the polishing apparatus, the grooves can be provided in parallel with each other. The grooves can have a grid-like or radial configuration. It is preferable that a rotation center of the turn table receiving member and a rotation center of the work are different from each other. Thereby, the contact pressure between the polishing pad and the work is substantially averaged.
The work can include a semiconductor wafer. In a case of a work, such as a semiconductor wafer that is extremely thin and is required extremely high flatness, an effect obtained by applying the method or the apparatus according to the present invention is particularly remarkable.
It is preferable that a plurality of grooves are provided as the groove and that widths of the grooves are within 3 to 15 mm, spacings of the grooves are within 10 to 100 mm and depths of the grooves are within 1 to 10 mm, respectively. Particularly, when a semiconductor wafer is polished with the present invention, good flatness can be obtained when the grooves are within the ranges, further, detachment of the turn table from the turn table receiving member becomes easy.
REFERENCES:
patent: 5584750 (1996-12-01), Ishida et al.
patent: 5704827 (1998-01-01), Nishi et al.
patent: 5904609 (1999-05-01), Fukuroda
patent: 5972162 (1999-10-01), Cesna
patent: 5975986 (1999-11-01), Allen
patent: 5997390 (1999-12-01), Hose
patent: 6206769 (2001-03-01), Walker
patent: 6213855 (2001-04-01), Natalico
patent: 0 845 328 A2 (1998-06-01), None
patent: U-61-175352 (1986-10-01), None
patent: A-5-237761 (1993-09-01), None
Masumura Hisashi
Okamura Kouichi
Suzuki Fumio
Hail III Joseph J.
Oliff & Berridg,e PLC
Shanley Daniel
Shin-Etsu Handotai & Co., Ltd.
LandOfFree
Polishing method and polishing device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polishing method and polishing device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polishing method and polishing device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2563345