U.S. patent application number 09/922311 was filed with the patent office on 2002-08-01 for polishing method using dynamic feedback recipe.
Invention is credited to Chou, Liang-Kuei, Huang, Chi-Yeh, Lee, Chi-Hung, Lee, Chih-Hung, Liu, Kuo-Ju.
Application Number | 20020102917 09/922311 |
Document ID | / |
Family ID | 21677168 |
Filed Date | 2002-08-01 |
United States Patent
Application |
20020102917 |
Kind Code |
A1 |
Lee, Chih-Hung ; et
al. |
August 1, 2002 |
Polishing method using dynamic feedback recipe
Abstract
A polishing method using a dynamic feedback recipe is disclosed.
The polishing method includes steps of providing a first recipe,
polishing a first wafer according to the first recipe, measuring
the first wafer to obtain a first determined data from the first
wafer, calculating a second recipe according to a specific equation
and the first determined data, and replacing the first recipe with
the second recipe and polishing a second wafer according to the
second recipe.
Inventors: |
Lee, Chih-Hung; (Hsinchu,
TW) ; Huang, Chi-Yeh; (Hsinchu, TW) ; Lee,
Chi-Hung; (Hsinchu, TW) ; Liu, Kuo-Ju;
(Hsinchu, TW) ; Chou, Liang-Kuei; (Hsinchu,
TW) |
Correspondence
Address: |
COZEN AND O'CONNOR
1900 MARKET STREET
PHILADELPHIA
PA
19103
US
|
Family ID: |
21677168 |
Appl. No.: |
09/922311 |
Filed: |
July 21, 2001 |
Current U.S.
Class: |
451/21 |
Current CPC
Class: |
B24B 49/16 20130101;
B24B 37/013 20130101; B24B 37/042 20130101; B24B 49/006
20130101 |
Class at
Publication: |
451/21 |
International
Class: |
B24B 007/22 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 30, 2001 |
TW |
090101830 |
Claims
What is claimed is:
1. A polishing method using a dynamic feedback recipe, comprising
steps of: providing a first recipe; polishing a first wafer
according to said first recipe; measuring said first wafer to
obtain a first determined data from said first wafer; calculating a
second recipe according to a specific equation and said first
determined data; and replacing said first recipe with said second
recipe and polishing a second wafer according to said second
recipe.
2. The method according to claim 1, wherein each of said first
wafer and said second wafer comprises an integrated circuit (IC)
thereon.
3. The method according to claim 1, wherein said first recipe is a
predetermined recipe.
4. The method according to claim 1, wherein said first wafer is
driven by a carrier and polished by a polishing pad via a relative
motion.
5. The method according to claim 4, further comprising a carrier
film disposed between said carrier and said first wafer for
protecting said first wafer.
6. The method according to claim 1, wherein said second wafer is
driven by a carrier and polished by a polishing pad via a relative
motion.
7. The method according to claim 1, wherein said polishing method
is a chemical mechanical polishing method employing a chemical
mechanical polishing apparatus.
8. The method according to claim 1, wherein said specific equation
is stored in a dynamic recipe calculating device.
9. The method according to claim 1, wherein said first recipe and
second recipe are selected from one group consisting of a rotation
speed and a pressure of said carrier, a rotation speed and a
pressure of a turn table in a polishing apparatus, a back side
pressure (BSP), a slurry flow rate, a dressing time and a dressing
pressure of a pad conditioner and a combination thereof.
10. The method according to claim 9, wherein said first determined
data is obtained by a measuring apparatus which is disposed in said
polishing apparatus.
11. The method according to claim 9, wherein said first determined
data is obtained by a measuring apparatus which is disposed out of
said polishing apparatus.
12. The method according to claim 1, wherein said first determined
data is a ratio of a central removed amount and an edge removed
amount of said wafer.
13. The method according to claim 1, wherein said specific equation
is y.sub.2=y.sub.1+a (y.sub.0-y.sub.1)+b, and a is said first
determined data, y is a recipe for adjusting, and b is a
coefficient.
14. The method according to claim 1, further comprising steps of:
providing a plurality of wafers; measuring said second wafer to
obtain a second determined data from said second wafer; calculating
a third recipe according to said specific equation and said second
determined data; replacing said second recipe with said third
recipe and polishing a third wafer according to said third recipe;
and repeating said measuring step, said calculating step, and
polishing step to said plural wafers till said plural wafers are
polished to obtain a plurality of polished wafers.
15. The method according to claim 14, wherein said specific
equation is y.sub.i+2=y.sub.i+1+a (y.sub.i-y.sub.i-1)+b, and a is
said first determined data, y is a recipe for adjusting,
i=0.about.n and b is a coefficient.
16. The method according to claim 14, further comprising a testing
step after polishing for a certain period of time.
17. The method according to claim 16, wherein said testing step
comprises: providing a test wafer selected from said plurality of
polished wafers; polishing said test wafer according to a testing
recipe; and calculating a removed amount of said test wafer to
obtain a polishing rate and an uniformity of said test wafer for
determining whether to change said polishing pad.
18. The method according to claim 17, wherein said test wafer is a
blank wafer having a film thereon.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a polishing method using a
dynamic feedback recipe, and more particularly to a chemical
mechanical polishing method using a dynamic feedback recipe.
BACKGROUND OF THE INVENTION
[0002] FIG. 1 is a cutaway view illustrating polishing apparatus
according to the prior art. A wafer 10 is polished by a chemical
mechanical polishing apparatus including a carrier 12 and a carrier
film 14. Generally, because the polishing rates are different in
the center and the edge of the wafer 10, a back side pressure 11 is
applied in the wafer 10 to change the central polishing rate of the
wafer 10 for approaching a consist polishing rate for the whole
wafer 10 and achieving a preferred non-uniformity.
[0003] For maintaining the non-uniformity of the wafer 10 in a
specification limit, the methods for using the back side pressure
11 or the carrier 12 oscillation can reduce the difference between
the central and the edge of the polishing rate. However, along with
consuming and deforming of a polishing pad 13, the central
polishing rate of the wafer 10 is gradually increased or decreased
whereas the edge polishing rate of that is slightly changed.
Therefore, the ratio of the central removed amount and the edge
removed amount of the wafer is proportional to the non-uniformity
of the wafer.
[0004] Accordingly, the typical polishing method for the wafer
includes the following disadvantages:
[0005] 1. At the beginning of using a new polishing pad, the
central polishing rate is much faster than the edge polishing rate,
which causing a poor non-uniformity. Therefore, it is necessary to
use a lot of wafers for initially breaking in, a lot of slurry and
about 5-10 hours to proceed the breaking in. Thus, it really takes
time and wastes material.
[0006] 2. At the last phase of the polishing pad, the difference
between the central polishing rate and the edge polishing rate is
too big and over the specification limit. It is necessary to
replace the polishing pad, so the life time of the polishing pad is
short.
[0007] 3. The non-uniformity of the wafer is a critical indicator
for the flatness of the wafer. However, the non-uniformity of the
wafer according to the prior art only can be controlled in the
specification limit, and cannot achieve a preferred condition.
[0008] Therefore, the purpose of the present invention is to
develop a method to deal with the above situations encountered in
the prior art.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of the present invention to
propose a polishing method using a dynamic feedback recipe for
reducing an initial time of breaking in.
[0010] It is therefore another object of the present invention to
propose a polishing method using a dynamic feedback recipe for
achieving a preferred non-uniformity of the wafer.
[0011] It is therefore an additional object of the present
invention to propose a polishing method using a dynamic feedback
recipe for stabilizing a polishing rate of the wafer.
[0012] It is therefore an additional object of the present
invention to propose a polishing method using a dynamic feedback
recipe for increasing up time of the production machine, the
producing yield, and reducing the cost.
[0013] According to the present invention, there is proposed a
polishing method using a dynamic feedback recipe. The polishing
method includes steps of providing a first recipe, polishing a
first wafer according to the first recipe, measuring the first
wafer to obtain a first determined data from the first wafer,
calculating a second recipe according to a specific equation and
the first determined data, and replacing the first recipe with the
second recipe and polishing a second wafer according to the second
recipe.
[0014] Preferably, each of the first wafer and the second wafer
comprises an integrated circuit (IC) thereon.
[0015] Preferably, the first recipe is a predetermined recipe.
[0016] Preferably, the first wafer is driven by a carrier and
polished by a polishing pad via a relative motion. Preferably, the
method further includes a carrier film disposed between the carrier
and the first wafer for protecting the first wafer. Preferably, the
second wafer is driven by a carrier and polished by a polishing pad
via a relative motion.
[0017] Preferably, the polishing method is a chemical mechanical
polishing method employing a chemical mechanical polishing
apparatus.
[0018] Preferably, the specific equation is stored in a dynamic
recipe calculating device.
[0019] Certainly, the first recipe and second recipe can be a
rotation speed and a pressure of the carrier, a rotation speed and
a pressure of a turn table in a polishing apparatus, a back side
pressure (BSP), a slurry flow rate, a dressing time and a dressing
pressure of a pad conditioner or a combination thereof.
[0020] Certainly, the first determined data can be obtained by a
measuring apparatus which is disposed in the polishing apparatus or
out of the polishing apparatus. Preferably, the first determined
data is a ratio of a central removed amount and an edge removed
amount of the wafer.
[0021] Preferably, the specific equation is y.sub.2=y.sub.1+a
(y.sub.0-y.sub.1)+b, and a is the first determined data, y is a
recipe for adjusting, and b is a coefficient.
[0022] Preferably, the polishing method further includes steps of
providing a plurality of wafers, measuring the second wafer to
obtain a second determined data from the second wafer, calculating
a third recipe according to the specific equation and the second
determined data, replacing the second recipe with the third recipe
and polishing a third wafer according to the third recipe, and
repeating the measuring step, the calculating step, and polishing
step to the plural wafers till the plural wafers are polished to
obtain a plurality of polished wafers. Preferably, the specific
equation is y.sub.i+2=y.sub.i+1+a (y.sub.i-y.sub.i+1)+b, and a is
the first determined data, y is a recipe for adjusting, i is an
integer from 0 to n, and b is a coefficient.
[0023] Preferably, the polishing method further includes a testing
step after polishing for a certain period of time. The testing step
preferably includes providing a test wafer selected from the
plurality of polished wafers, polishing the test wafer according to
a testing recipe, and calculating a removed amount of the test
wafer to obtain a polishing rate and an uniformity of the test
wafer for determining whether to change the polishing pad.
Certainly, the test wafer is a blank wafer having a film
thereon.
[0024] The present invention may best be understood through the
following description with reference to the accompanying drawings,
in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a cutaway view illustrating polishing apparatus
according to the prior art;
[0026] FIG. 2 is a flow chart illustrating a polishing method using
a dynamic feedback recipe according to the present invention;
and
[0027] FIGS. 3A-3B are block diagrams illustrating a polishing
method using a dynamic feedback recipe according to preferred
embodiments of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] FIG. 2 is a flow chart illustrating a polishing method using
a dynamic feedback recipe according to the present invention. As
shown in FIG. 2, after changing a new polishing pad, a blank wafer
is provided for initially breaking in. Sequentially, a first wafer
is polished by using a first recipe. After measuring the first
wafer which has been polished to obtain a determined data, a second
recipe is obtained by a specific equation. The second recipe is
transferred to a chemical mechanical polishing apparatus for
replacing the first recipe and is used for polishing a second
wafer. After measuring the second wafer which has been polished to
obtain a second determined data, a third recipe is obtained by the
specific equation. The third recipe is transferred to a chemical
mechanical polishing apparatus for replacing the second recipe and
is used for polishing a third wafer. Accordingly, a fourth, fifth .
. . wafers are polished by the feedback recipes. The first recipe
is a predetermined recipe which is tuned by users. The
predetermined recipe can be changed according to the particular
requirement.
[0029] After a certain period of time or a bath of wafer is
polished, a testing step is proceeded to decide whether the
polishing pad should be changed or not. The testing step includes
providing a test wafer selected from the polished wafers, polishing
the test wafer according to a testing recipe, and calculating a
removed amount of the test wafer to obtain a polishing rate and an
uniformity of the test wafer for determining whether to change the
polishing pad. The test wafer is a blank wafer with a film thereon.
The testing recipe is obtained by tuning. The certain time and the
testing recipe can be changed according to the particular
requirement.
[0030] The chemical mechanical polishing apparatus includes a
carrier to drive the wafer for polishing by a polishing pad via a
relative motion. The carrier has a carrier film between the carrier
and the wafer for protecting the wafer. Each wafer has an
integrated circuit thereon.
[0031] The above recipes includes a carrier rotation speed, a
carrier pressure, a rotation speed and a pressure of a turn table
in the polishing apparatus, a back side pressure (BSP), a slurry
flow rate, a dressing time and a dressing pressure of a pad
conditioner or a combination thereof.
[0032] The specific equation stored in a dynamic recipe calculating
device is y.sub.i+2=y.sub.i+1+a (y.sub.i-y.sub.i+1)+b, wherein a is
the first determined data, y is a recipe for adjusting, i=0.about.n
and b is a coefficient. The first determined data is a ratio of a
central removed amount and an edge removed amount of the wafer.
[0033] As shown in FIGS. 3A and 3B, the predetermined preset
recipe, e.g. the first recipe is inputted into a central
information manager (CIM) computer 32, and transferred from the
central information manager computer 32 to a dynamic recipe
calculating device 31. A compensated recipe, e.g. the second recipe
is calculated and obtained by the dynamic recipe calculating device
31 according to the specific equation and the first determined
data, and transferred back to the central information manager
computer 32. Finally, the compensated recipe is transferred to a
chemical mechanical polishing apparatus 30 for polishing the
wafer.
[0034] In addition, a measuring apparatus 33 is disposed in the
chemical mechanical polishing apparatus 30 as shown in FIG. 3B
whereas a measuring apparatus (not shown) is disposed out of the
chemical mechanical polishing apparatus 30 as shown in FIG. 3A.
Thus, the determined data is automatically obtained by the
measuring apparatus 33 and is feedback to the dynamic recipe
calculating device 31 as shown in FIG. 3B. However, when the
measuring apparatus is out of the chemical mechanical polishing
apparatus 30, the polished wafer is taken to the measuring
apparatus by operators to measure the determined data, and the
determined data is inputted to the central information manager
computer 32 by operators. The measuring apparatus is in situ.
[0035] In sum, the polishing method using the dynamic feedback
recipe according to the present invention can efficiently solve the
problems of the long initial time for breaking in and the short
life time of the polishing pad. In addition, the polishing method
can achieve the preferred non-uniformity of the wafer, stabilize
the polishing rate, increase the producing yield, and reduce the
slurry consumption.
[0036] While the invention has been described in terms of what are
presently considered to be the most practical and preferred
embodiments, it is to be understood that the invention need not to
be limited to the disclosed embodiment. On the contrary, it is
intended to cover various modifications and similar arrangements
included within the spirit and scope of the appended claims which
are to be accorded with the broadest interpretation so as to
encompass all such modifications and similar structures.
* * * * *