U.S. patent application number 12/801555 was filed with the patent office on 2011-06-09 for method for predicting the polishing characteristics and life-span of a soft polishing pad.
This patent application is currently assigned to NATIONAL CHUNG CHENG UNIVERSITY. Invention is credited to Pay-Yau Huang, Yeau-Ren Jeng, Yu-Jeng Lin, Yu-Shaung Lin.
Application Number | 20110136407 12/801555 |
Document ID | / |
Family ID | 44082482 |
Filed Date | 2011-06-09 |
United States Patent
Application |
20110136407 |
Kind Code |
A1 |
Jeng; Yeau-Ren ; et
al. |
June 9, 2011 |
Method for predicting the polishing characteristics and life-span
of a soft polishing pad
Abstract
A method for predicting the polishing characteristics and
life-span of a soft polishing pad includes the steps of: (a)
establishing a matching database by means of performing a series of
dynamic analysis tests on a new soft polishing pad by a contact
probe at different frequencies and under different loads and
detecting the surface reaction of the new soft polishing pad, (b)
performing a dynamic analysis test on a to-be-tested soft polishing
pad by a contact probe at a predetermined frequency and under a
predetermined load and detecting the surface reaction of the
to-be-tested soft polishing pad, and (c) comparing the surface
reaction data of the to-be-tested soft polishing pad with the
matching database and predicting the polishing characteristics and
life-span of the to-be-tested soft polishing pad subject to the
comparison result. Subject to the aforesaid steps, the polishing
characteristics and life-span of the to-be-tested soft polishing
pad can be predicted without making an actual polishing test,
thereby saving a large amount of time and cost.
Inventors: |
Jeng; Yeau-Ren; (Tainan,
TW) ; Lin; Yu-Shaung; (Kaohsiung County, TW) ;
Huang; Pay-Yau; (Taipei City, TW) ; Lin; Yu-Jeng;
(Taichung City, TW) |
Assignee: |
NATIONAL CHUNG CHENG
UNIVERSITY
CHIA-YI
TW
|
Family ID: |
44082482 |
Appl. No.: |
12/801555 |
Filed: |
June 15, 2010 |
Current U.S.
Class: |
451/5 |
Current CPC
Class: |
B24B 37/042 20130101;
B24B 49/16 20130101; G01N 3/32 20130101; G01N 2203/0282 20130101;
G01N 3/56 20130101; G01N 2203/0019 20130101; B24B 37/20 20130101;
G01N 2203/0676 20130101 |
Class at
Publication: |
451/5 |
International
Class: |
B24B 49/00 20060101
B24B049/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 3, 2009 |
TW |
98141405 |
Claims
1. A method for predicting the polishing characteristics and
life-span of a soft polishing pad, comprising the steps of: (A)
preparing a new soft polishing pad having polishing characteristics
that are known, and then performing a series of dynamic analysis
tests to oscillate said new soft polishing pad with contact probe
at different oscillation frequencies and under different loads, and
then detecting the surface reaction of said new soft polishing pad
during every dynamic analysis test, and then using the tested data
and the known polishing characteristics of said new soft polishing
pad to establish a matching database; (B) preparing a to-be-tested
soft polishing pad for polishing a predetermined workpiece and then
performing a dynamic analysis test to oscillate said to-be-tested
soft polishing pad at a predetermined oscillation frequency and
under a predetermined load and then detecting the surface reaction
of said to-be-tested soft polishing pad during the dynamic analysis
test; and (C) comparing the surface reaction of said to-be-tested
soft polishing pad with the data of said matching database to
predict the polishing characteristics and life-span of said
to-be-tested soft polishing pad.
2. The method for predicting the polishing characteristics and
life-span of a soft polishing pad as claimed in claim 1, wherein
the dynamic analysis tests performed in step (A) and step (B) are
to apply a cyclic stress to the surface of said new soft polishing
pad or said to-be-tested soft polishing pad perpendicularly when
said new soft polishing pad or said to-be-tested soft polishing pad
is being oscillated.
3. The method for predicting the polishing characteristics and
life-span of a soft polishing pad as claimed in claim 2, wherein
said cyclic stress is applied to the surface of said new soft
polishing pad or said to-be-tested soft polishing pad through a
contact probe, said contact probe having a geometric shape
predetermined subject to the configuration of the surface
asperities of said predetermined workpiece.
4. The method for predicting the polishing characteristics and
life-span of a soft polishing pad as claimed in claim 1, wherein
detecting the surface reaction of said new soft polishing pad
during step (A) and detecting the surface reaction of said
to-be-tested soft polishing pad during step (B) are done by means
of using a pressure sensor to measure the surface reaction force of
said new soft polishing pad and said to-be-tested soft polishing
pad.
5. The method for predicting the polishing characteristics and
life-span of a soft polishing pad as claimed in claim 1, wherein
the predetermined loads during step (A) and step (B) include static
loads and dynamic loads.
6. The method for predicting the polishing characteristics and
life-span of a soft polishing pad as claimed in claim 5, wherein
the value of the static load applied during step (B) is determined
subject to the pressure to be applied to said to-be-tested soft
polishing pad during an actual polishing process.
7. The method for predicting the polishing characteristics and
life-span of a soft polishing pad as claimed in claim 5, wherein
the value of the dynamic load applied during step (B) is determined
subject to the pressure to the average height of the surface
asperities of said predetermined workpiece.
8. The method for predicting the polishing characteristics and
life-span of a soft polishing pad as claimed in claim 1, wherein
the value of the oscillation frequency set during step (B) is
determined subject to the distribution density of the surface
asperities of said predetermined workpiece.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to polishing technology and
more particularly, to a method for predicting the polishing
characteristics and life-span of a soft polishing pad.
[0003] 2. Description of the Related Art
[0004] Polishing or lapping is a post processing process for the
surface finishing of a precision workpiece to have the surface
roughness and planarity of the precision workpiece be within a
tolerable range. Using a polishing pad to perform a polishing
process is one of the main surface finishing techniques.
[0005] Before entering the polishing process, a soft polishing pad
having suitable polishing characteristics (such as surface
roughness) is selected subject to the workpiece to be polished so
that the best polishing efficiency and quality can be obtained.
[0006] In another word, knowing the polishing characteristics and
life-span of a soft polishing pad and the effect of a polishing pad
on different workpieces is the key point to select the right
polishing pad.
[0007] However, the commonly adopted method of obtaining the data
of the polishing characteristics of a polishing pad and predicting
its life-span is to perform a large number of actual polishing
tests. This method wastes much time and cost.
SUMMARY OF THE INVENTION
[0008] The present invention has been accomplished under the
circumstances in view. It is the main object of the present
invention to provide a method for predicting the polishing
characteristics and life-span of a soft polishing pad, which
predicts the polishing characteristics and life-span of a polishing
pad rapidly without any actual polishing test, thereby saving much
time and cost.
[0009] To achieve this and other objects of the present invention,
a method for predicting the polishing characteristics and life-span
of a polishing pad includes the steps of: (a) preparing a new soft
polishing pad having polishing characteristics that are known, and
then performing a series of dynamic analysis tests to oscillate the
new soft polishing pad by a contact probe at different oscillation
frequencies and under different loads, and then detecting the
surface reaction of the new polishing pad during every dynamic
analysis test, and then using the tested data and the known
polishing characteristics of the new soft polishing pad to
establish a matching database; (b) preparing a to-be-tested soft
polishing pad for polishing a predetermined workpiece and then
performing a dynamic analysis test to oscillate the to-be-tested
polishing pad at a predetermined oscillation frequency and under a
predetermined load and then detecting the surface reaction of the
to-be-tested polishing pad; and (c) comparing the surface reaction
of the to-be-tested polishing pad with the data of the matching
database to predicate the polishing characteristics and life-span
of the to-be-tested polishing pad. Subject to the aforesaid steps,
the polishing characteristics and life-span of the to-be-tested
polishing pad can be predicted without making an actual polishing
test, thereby saving a large amount of time and cost.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a flow chart of a method for predicting the
polishing characteristics and life-span of a soft polishing pad in
accordance with the present invention.
[0011] FIG. 2 is a schematic drawing showing the operation status
of step (A) of the method for predicting the polishing
characteristics and life-span of a soft polishing pad in accordance
with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Referring to FIG. 1, a method for predicting the polishing
characteristics and life-span of a soft polishing pad in accordance
with the present invention includes the following steps
(A)-(C).
[0013] In step (A), prepare a new soft polishing pad 11 of which
the polishing characteristics are known, and then perform a series
of dynamic analysis tests to oscillate the new polishing pad 11 at
different oscillation frequencies and under different loads.
According to the present preferred embodiment, the dynamic analysis
tests are performed through a contact probe 12 subject to the use
of a cam mechanism, piezoelectric device or any other means
controllable to produce a cyclic stress F1 that is applied to the
surface 111 of the new polishing pad 11 perpendicularly, thereby
simulating the conditions in which surface asperities of different
workpieces (wafer or metal surface) are moved over the surface of
the polishing pad 11.
[0014] Further, the reaction of the surface 111 of the new
polishing pad 11 is detected during every dynamic analysis test.
When the cyclic stress F1 is applied to the surface 111 of the new
polishing pad 11, a relative reaction force F2 is produced.
According to the present preferred embodiment, a pressure sensor
(for example, load cell) 13 is installed in the contact probe 12 to
measure the reaction force F2.
[0015] Thereafter, the tested data and the known polishing
characteristics of the new polishing pad 11 are used to establish a
matching database.
[0016] It is to be understood that, for the sake of simulating a
real polishing surfactant behavior, the value of the oscillation
frequency for each test can be set subject to the distribution
density of the surface asperities of the workpiece to be polished
in the simulation. Further, the aforesaid loads include static
loads and dynamic loads. The values of static loads are determined
subject to the pressure P to be applied to the new polishing pad 11
in the actual polishing process. The values of dynamic loads are
determined subject to the average height of the surface asperities
of the workpiece to be polished in the simulation. Further, the
geometric shape of the aforesaid contact probe 12 can be determined
subject to the shape characteristics of the surface asperities of
the workpiece to be polished in the simulation. Subject to the
aforesaid settings, the simulation is more close to the real
operation, improving test accuracy.
[0017] After step (A), step (B) is performed as follows, with
reference to FIG. 3:
[0018] In step (B), prepare a to-be-tested soft polishing pad 13
for polishing a predetermined workpiece (the polishing
characteristics and life-span of the to-be-tested soft polishing
pad 13 are unknown), and then perform a dynamic analysis test to
oscillate the to-be-tested soft polishing pad 13 by a contact probe
12 at a predetermined oscillation frequency and under a
predetermined load and apply a cyclic stress F3 to the surface 141
of the to-be-tested soft polishing pad 14 perpendicularly, and then
use the same pressure sensor (load cell) 13 to measure the reaction
force F4 of the surface 141 of the to-be-tested soft polishing pad
14. It is to be understood that, for the sake of simulating a real
polishing surfactant behavior, the value of the oscillation
frequency of the dynamic analysis test is set subject to the
distribution density of the surface asperities of the workpiece to
be polished. The value of the static load or dynamic load is
determined in the same manner as step (A).
[0019] After step (B), step (C) is finally performed as
follows:
[0020] In step (C), compare the reaction (the reaction force F4
according to the present preferred embodiment) of the surface 141
of the to-be-tested soft polishing pad 14 with the data of the
matching database obtained in step (A), and then predict the
polishing characteristics and life-span of the to-be-tested soft
polishing pad 14 subject to the comparison result.
[0021] Subject to the performance of the aforesaid steps, the
polishing characteristics and life-span of the to-be-tested soft
polishing pad can be predicted without making an actual polishing
test, thereby saving a large amount of time and cost.
* * * * *