High-rate polishing method
View Patent ↗The invention provides a method for polishing at least one of a magnetic, optical and semiconductor substrate in the presence of a polishing medium with a polishing pad. The substrate is fixed within a carrier fixture having a channel-free surface. The method comprises securing the substrate in the carrier fixture with the channel-free surface adjacent and parallel to a polishing surface of the polishing pad. The polishing pad has multiple grooves with high-rate paths. The method includes applying polishing medium to the polishing pad adjacent the carrier fixture; and rotating the polishing pad and carrier fixture to polish the substrate with the polishing pad and the polishing medium wherein the channel-free surface of the carrier fixture presses against the polishing pad to impede flow of the polishing medium into the substrate and the high-rate groove paths traverse the carrier fixture to promote flow of the polishing medium to the substrate.
1. A method for polishing at least one of a magnetic, optical and semiconductor substrate in the presence of a polishing medium with a polishing pad, the substrate being fixed within a carrier fixture, the carrier fixture having a channel-free surface, the method comprising:
a) securing the substrate in the carrier fixture with the channel-free surface adjacent and parallel to a polishing surface of the polishing pad, the polishing pad having multiple grooves, the multiple grooves having a high-rate path, at least fifty percent of the high-rate path being within twenty percent of a groove trajectory φ(r) in polar coordinates referenced to a concentric center of the polishing pad and defined in terms of (1) distance R between the concentric center of the polishing pad and the rotational center of the substrate being polished, (2) radius R c of the carrier fixture, and (3) local angle θ c0 of imaginary grooves in the carrier fixture, as follows:
ϕ
(
r
)
=
∫
R
-
R
C
r
R
R
C
sin
ϕ
c
+
(
tan
θ
c
0
)
(
R
R
C
cos
ϕ
c
+
1
)
(
R
R
C
cos
ϕ
c
+
1
)
-
(
tan
θ
c
0
)
R
R
C
sin
ϕ
c
ⅆ
r
′
r
′
where
ϕ
c
=
cos
-
1
(
R
2
+
R
C
2
-
r
2
2
RR
C
)
-
π
for
values
of
r
from
(
R
-
R
C
)
to
(
R
+
R
C
)
b) applying polishing medium to the polishing pad adjacent the carrier fixture; and
c) rotating the polishing pad and carrier fixture to polish the substrate with the polishing pad and the polishing medium wherein the channel-free surface of the carrier fixture presses against the polishing pad to impede flow of the polishing medium into the substrate and the high-rate groove paths traverse the carrier fixture to promote flow of the polishing medium to the substrate.
2. The method of claim 1 wherein the polishing pad has a center and the polishing occurs with multiple grooves that initiate with staggered radii from the center.
3. The method of claim 1 wherein the rotating occurs with the polishing pad rotating in a counterclockwise direction for φ c (r) being negative or in a clockwise direction for φ c (r) being positive.
4. The method of claim 1 wherein the polishing occurs with the high-rate path being within twenty percent of the groove trajectory with a θ c0 of 0 to 90 degrees.
5. A method for polishing at least one of a magnetic, optical and semiconductor substrate in the presence of a polishing medium with a polishing pad, the substrate being fixed within a carrier fixture, the carrier fixture having a channel-free surface, the method comprising:
a) securing the substrate in the carrier fixture with the channel-free surface adjacent and parallel to a polishing surface of the polishing pad, the polishing pad having multiple grooves, the multiple grooves having a high-rate path, at least fifty percent of the high-rate path being within twenty percent of a groove trajectory φ(r) in polar coordinates referenced to a concentric center of the polishing pad and defined in terms of (1) distance R between the concentric center of the polishing pad and the rotational center of the substrate being polished, (2) radius R c of the carrier fixture, and (3) local angle θ c0 of imaginary grooves in the carrier fixture, as follows:
ϕ
(
r
)
=
∫
R
-
R
C
r
R
R
C
sin
ϕ
c
+
(
tan
θ
c
0
)
(
R
R
C
cos
ϕ
c
+
1
)
(
R
R
C
cos
ϕ
c
+
1
)
-
(
tan
θ
c
0
)
R
R
C
sin
ϕ
c
ⅆ
r
′
r
′
where
ϕ
c
=
cos
-
1
(
R
2
+
R
C
2
-
r
2
2
RR
C
)
-
π
for
values
of
r
from
(
R
-
R
C
)
to
(
R
+
R
C
)
b) applying polishing medium to the polishing pad adjacent the carrier fixture; and
c) rotating the polishing pad and carrier fixture in the same direction to polish the substrate with the polishing pad and the polishing medium wherein the channel-free surface of the carrier fixture presses against the polishing pad to impede flow of the polishing medium into the substrate and the high-rate groove paths traverse the carrier fixture to promote flow of the polishing medium to the substrate.
6. The method of claim 5 wherein the polishing pad has a center and the polishing occurs with multiple grooves that initiate with staggered radii from the center.
7. The method of claim 5 wherein the rotating occurs with the polishing pad rotating in a counterclockwise direction for φ c (r) being negative or in a clockwise direction for φ c (r) being positive.
8. The method of claim 5 wherein the polishing occurs with uneven angular spacing between ones of the multiple grooves having a high-rate path.
9. The method of claim 5 wherein the polishing occurs with the high-rate path being within twenty percent of the groove trajectory with a θ c0 of 30 to 60 degrees.
10. The method of claim 5 wherein the polishing occurs with the high-rate path being within ten percent of the groove trajectory with a θ c0 at 40 to 50 degrees.