U.S. patent application number 09/973989 was filed with the patent office on 2002-06-20 for high accuracy blast processing method and high accuracy blast processing apparatus.
Invention is credited to Hobo, Yasuo, Izawa, Moriyasu, Sakai, Shigekazu, Watanabe, Noboru.
Application Number | 20020077042 09/973989 |
Document ID | / |
Family ID | 18808530 |
Filed Date | 2002-06-20 |
United States Patent
Application |
20020077042 |
Kind Code |
A1 |
Izawa, Moriyasu ; et
al. |
June 20, 2002 |
High accuracy blast processing method and high accuracy blast
processing apparatus
Abstract
In a high accuracy blast processing method of the present
invention which is a blast processing method for processing a
substrate by injecting an injection material from a nozzle by
compressed air, injection of the injection material is either
intermittent injection for repeating the injection and injection
stop at short intervals or a combination of the intermittent
injection and continuous injection. By doing so, even if a
processing progresses, processing efficiency is not deteriorated
and a non-processing target region is not damaged even without
using a mask. A high accuracy blast processing apparatus of the
present invention consists of a nozzle unit forcedly feeding the
injection material to the nozzle by the compressed air and a work
table moving the substrate horizontally and vertically. A solenoid
valve for injecting and stopping the injection material and a
control unit outputting an intermittent operating signal to the
solenoid valve are connected to the nozzle unit.
Inventors: |
Izawa, Moriyasu;
(Nishikasugai-gun, JP) ; Watanabe, Noboru;
(Nishikasugai-gun, JP) ; Hobo, Yasuo;
(Nishikasugai-gun, JP) ; Sakai, Shigekazu;
(Nishikasugai-gun, JP) |
Correspondence
Address: |
PARKHURST & WENDEL, L.L.P.
Suite 210
1421 Prince Street
Alexandria
VA
22314-2805
US
|
Family ID: |
18808530 |
Appl. No.: |
09/973989 |
Filed: |
October 11, 2001 |
Current U.S.
Class: |
451/75 |
Current CPC
Class: |
B24C 1/045 20130101 |
Class at
Publication: |
451/75 |
International
Class: |
B24C 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 2000 |
JP |
2000-332306 |
Claims
What is claimed is:
1. A high accuracy blast processing method for processing a
substrate by injecting an injection material from a nozzle by
compressed air, wherein injection of the injection material is
intermittent injection for repeating injection and injection stop
at short intervals.
2. A high accuracy blast processing method for processing a
substrate by injecting an injection material from a nozzle by
compressed air, wherein injection of the injection material is a
combination of intermittent injection for repeating injection and
injection stop at short intervals and continuous injection.
3. A high accuracy blast processing method according to claim 1 or
2, wherein the injection and the injection stop of the intermittent
injection are repeated at intervals of not more than 1 second.
4. A high accuracy blast processing method according to claim 1, 2
or 3, wherein the substrate is processed by injecting the injection
material having a mean particle diameter of not more than 50 .mu.m
and an injection quantity of not more than 50 g/min from the nozzle
having an inside diameter of 0.2 to 2 mm by the compressed air of
0.2 to 2.5 MPa.
5. A high accuracy blast processing apparatus comprising: a nozzle
unit forcedly feeding an injection material to a nozzle by
compressed air; and a work table moving a substrate horizontally
and vertically, wherein a control unit outputting an intermittent
operating signal for injecting and stopping the injection material
is connected to said nozzle unit.
6. A high accuracy blast processing apparatus comprising: a nozzle
unit forcedly feeding an injection material to a nozzle by
compressed air; and a work table moving a substrate horizontally
and vertically, wherein a solenoid valve for injecting and stopping
the injection material and a control unit outputting an
intermittent operating signal to the solenoid valve are connected
to said nozzle unit.
7. A high accuracy blast processing apparatus according to claim 5
or 6, wherein the nozzle unit is constituted of the nozzle having
an inside diameter of 0.2 to 2 mm and a mechanism for forcedly
feeding the injection material having a mean particle diameter of
not more than 50 .mu.m in a quantity of not more than 50 g/min to
the nozzle by the compressed air of 0.2 to 2.5 MPa.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a high accuracy blast
processing method for conducting perforation, cutting, patterning
to a substrate mainly consisting of hard, fragile material such as
silicon, glass or ceramic and a high accuracy blast processing
apparatus used therefor.
[0003] 2. Description of the Prior Art
[0004] As means for performing various processings including
perforating and cutting to a substrate consisting of a hard,
fragile material such as silicon, glass or ceramic and forming a
fine pattern thereon, a sand blasting method capable of conducting
a dry fine processing has been widely used. This processing method
is to continuously inject a microscopic projection material, such
as alumina or SiC, onto a processing target surface from a nozzle
by compressed air for a predetermined time to thereby blast the
processing target surface.
[0005] Assume that many transparent holes are formed in a substrate
at predetermined intervals by the above-stated blast processing
method. To prevent non-processing target regions from being
damaged, when one hole is perforated by the continuous injection of
an injection material which is moving in a nozzle, the injection is
temporarily stopped and the nozzle is moved to the next perforating
target position. Then, an injection material is injected again and
the perforating processing is conducted. In this case, however, the
injection material remains in a hose forcedly feeding the injection
material to the nozzle due to the stop of the injection, and the
residual injection material is injected together with the following
injection material at the time of the next perforating processing.
As a result, the injection material larger in quantity than that in
a stationary injection state is injected, disadvantageously
deteriorating processing accuracy.
[0006] Further, if perforating is conducted to form holes each
having a predetermined depth by continuously injecting an injection
material, it is difficult to discharge the injection material from
the holes which are not perforated yet in the middle of the
processing. As a result, the injection material remains in the
holes and prevent the holes from being further processed,
disadvantageously, greatly decreasing processing speed and
requiring a long time to complete the processing. Besides, a part
of the injection material is splashed over and collided on the
peripheries of the holes to be processed. Due to this, if it takes
a long time to form one hole, a non-processing target region around
the hole is disadvantageously roughened and damaged.
[0007] As means for preventing the collision of the injection
material on such a non-processing target regions, there are
proposed methods for masking the non-processing target region and
selectively blasting unmasked portions. For example, a method using
a photoresist as a mask enables carrying out the highest accuracy
processing. However, it is necessary to use a mask in the steps of
pattern transfer, development and drying using a photographic plate
as well as the step of peeling off and wash the mask after the
processing. The steps become disadvantageously complicated to
thereby push up cost. Besides, it is necessary to conduct a waste
liquid treatment. For these reasons, this method cannot be easily
adopted.
[0008] It is, therefore, an object of the present invention to
provide a high accuracy blast processing method and a high accuracy
blast processing apparatus capable of solving the above-stated
conventional disadvantages and accurately processing a substrate
without deteriorating processing efficiency even if the processing
progresses. It is another object of the present invention to
provide a high accuracy blast processing method and a high accuracy
blast processing apparatus capable of accurately processing a
substrate without damaging a non-processing target region even if a
mask is completely not used.
SUMMARY OF THE INVENTION
[0009] In a high accuracy blast processing method according to the
present invention which is a high accuracy blast processing method
for processing a substrate by injecting an injection material from
a nozzle by compressed air, injection of the injection material is
intermittent injection for repeating injection and injection stop
at short intervals. Thus, in a perforating processing, when the
processing progresses to a certain degree, the injection material
is discharged without remaining in a bottomed hole, making it
possible to prevent processing efficiency from being deteriorated
and to complete the processing in far shorter time than that in the
conventional method. In addition, it is possible to prevent the
splashed injection material from being collided on the injection
material which has been injected and to thereby prevent the
peripheral portion of the hole from being damaged by the spattering
and collision of the injection material. According to the high
accuracy blast processing method of the present invention,
therefore, it is possible to carry out a fine processing without
deteriorating processing efficiency even if the processing
progresses and without damaging a non-processing target region even
if a complete mask is not used.
[0010] According to the preferred embodiment of the present
invention, the high accuracy blast processing method in which the
injection of the injection material is intermittent injection for
repeating injection and injection stop at short intervals, is
conducted by combining the intermittent injection with continuous
injection. By doing so, it is possible to obtain a greater
advantage than that in case of conducting only the intermittent
injection. In addition, it is preferable that the injection and the
injection stop of the intermittent injection are repeated at
intervals of not more than 1 second. It is noted that it is the
most preferable for processing a substrate consisting of a hard,
fragile material such as silicon, glass or ceramic that the
substrate is processed by injecting the injection material having a
mean particle diameter of not more than 50 .mu.m and an injection
quantity of not more than 50 g/min from the nozzle having an inside
diameter of 0.2 to 2 mm by the compressed air of 0.2 to 2.5
MPa.
[0011] A high accuracy blast processing apparatus according to the
present invention is used for the above-stated high accuracy blast
processing method comprising: a nozzle unit forcedly feeding an
injection material to a nozzle by compressed air; and a work table
moving a substrate horizontally and vertically. A control unit
outputting an intermittent operating signal for injecting and
stopping the injection material is connected to the nozzle unit.
Alternatively, a solenoid valve may be attached to the nozzle unit
so as to inject and stop the injection material in response to a
signal applied from the control unit. This control unit turns on
and off the nozzle unit at predetermined intervals to thereby allow
the injection material to be intermittently injected. Besides, the
quantity of the injection material remaining in the hose is greatly
reduced even if the injection is completely stopped, thereby
maintaining processing accuracy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view showing the constitution of a
high accuracy blast processing apparatus according to the present
invention;
[0013] FIG. 2 is a graph showing changes in the depths of holes
relative to injection time for injecting an injection material
according to the present invention; and
[0014] FIG. 3 is a graph showing changes in the diameters of holes
relative to injection time for injecting the injection material by
the method of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] The preferred embodiment of the present invention will be
described hereinafter with reference to the drawings.
[0016] FIG. 1 shows one example of a high accuracy blast processing
apparatus according to the present invention. In FIG. 1, reference
numeral 1 denotes a substrate subjected to be blasted, 2 denotes a
nozzle unit for forcedly feeding an injection material to the
nozzle to inject the injection material, 3 denotes the nozzle, and
4 denotes a work table. The nozzle unit 2 is connected to a hose to
which the injection material as well as compressed air is supplied
from a hopper which is not shown in FIG. 1. Also, the nozzle unit
has a mechanism in which the injection material in a predetermined
quantity is forcedly fed to the nozzle 3 and injected therefrom.
Reference numerals 5 and 5 denote two solenoid valves, 6 denotes a
control unit setting a predetermined cycle time, outputs signals to
these solenoid valves 5 and thereby intermittently turns on and off
the solenoid valves 5. The control unit 6 is connected to the
nozzle unit 2 stated above. Then, out of the two solenoid valve 5,
one is used to shut off the injection material and the other is
used to shut off the compressed air. It is noted that a personal
computer, an NC unit, a sequencer or the like can be used as the
control unit 6. In addition, instead of employing the solenoid
valves in the apparatus shown in FIG. 1, a control unit
intermittently turning on and off an electric signal may be
directly connected to the nozzle unit so as to intermittently
inject the injection material. The work table 4 is moved
horizontally and vertically by an X axis slider 7, a Y axis slider
8 and a Z axis slider 9. The movement of the work table 4 is made
by transmitting movement signals to the respective sliders from the
control unit 6 through a motor driver 10.
[0017] A blast processing is carried out by disposing the nozzle 3
at the predetermined position of the substrate 1 and injecting an
injection material having predetermined mean particle diameters and
a predetermined quantity from the nozzle 3 at predetermined
pressure. Here, the inside diameter of the nozzle 3 is preferably
0.2 to 2 mm for the following reasons. If the inside diameter of
the nozzle 3 exceeds 2 mm, the processing accuracy of the apparatus
is deteriorated to make it difficult to conduct a desired
microscopic processing. If the inside diameter of the nozzle 3 is
less than 0.2 mm, the injection material becomes small in quantity
and the polishing and cleaning performance of the nozzle 3 is
deteriorated. In addition, if the mean particle diameter of the
injection material is large enough to exceed 50 .mu.m, the target
substrate cannot be processed sufficiently and microscopically. If
the mean particle diameter of the injection material is less than 5
.mu.m, sufficient polishing and cleaning performances cannot be
ensured. It is, therefore, preferable that the mean particle
diameter of the injection material is 5 to 50 .mu.m. It is noted
that the material of the injection material is not limited to
specific one and that powder such as alumina, SiC or silica sand
can be appropriately used.
[0018] Moreover, according to the present invention, it is
preferable that the injection material is injected by compressed
air at a pressure of 0.2 to 2.5 MPa for the following reasons. If
the pressure of the compressed air exceeds 2.5 MPa, the injection
material is splashed and spattered to a large degree and the
non-processing target regions of the substrate are badly damaged.
On the other hand, if the pressure of the compressed air is less
than 0.2 MPa, sufficient polishing and cleaning performance cannot
be ensured. Besides, if the injection quantity of the injection
material exceeds 50 g/min, the quantity of the injection material
remaining in the holes disadvantageously increases during the
perforating processing, which in turn deteriorates processing
efficiency. It, therefore, suffices that the injection quantity of
the injection material is not more than 50 g/min.
[0019] Further, to process the substrate, intermittent injection is
conducted, at least partially, so that the injection of the
injection material and the stop of the injection are alternately
repeated at short intervals. That is, in the perforating
processing, only intermittent injection is normally conducted. In a
cutting processing and a stop processing, it is effective to
combine intermittent injection for repeating the injection and the
stop of injection at short intervals and continuous injection so as
to inject the injection material. The injection in the combination
of the intermittent injection and the continuous injection will now
be described. In a cutting processing, it occurs less frequently
that it becomes difficult to discharge the injection material in
the middle of the processing as seen in the perforating processing.
Due to this, in the cutting processing, it basically suffices to
conduct only the continuous injection. If there are regions
requiring a highly accurate processing, the intermittent injection
may be partially conducted to such regions. Further, in the
injection stop processing for temporarily stopping the injection of
the injection material after the continuous injection, the
intermittent injection is utilized right after the start of the
processing and/or right before the end of the processing. The
reasons are as follows. The hose is interposed between the
injection material supply unit and the nozzle in the blasting
processing apparatus. Due to this, if injection is temporarily
stopped after the continuous injection, the injection material
remaining in the hose is injected together with the next injection
material when the next injection is started, with the result that
processing accuracy is disadvantageously deteriorated. By utilizing
the intermittent injection right after the start of the processing,
the injection material remaining in the hose is not injected at a
breath. By utilizing the intermittent injection right before the
end of the processing, a large quantity of the injection material
does not remain in the hose.
[0020] Furthermore, the interval between injection and injection
stop in this intermittent injection is preferably not more than 1
second. This is because if injection time and stop time exceed 1
second, respectively, processing efficiency and processing accuracy
are deteriorated. Needless to say, the intermittent injection in
this embodiment means that an injection material is intermittently
injected to process the substrate. The continuous injection means
that the injection material is continuously injected to process the
substrate. If the processing target portions of the substrate are
located at required intervals and the processing target is moved
from one processing target portion to the next processing target
portion, then it is defined that the injection is continuous
injection even if the injection is stopped during the movement of
the processing target portions. In the intermittent injection of
the injection material, the supply of either the compressed air or
the injection material may be stopped. More preferably, the
compressed air and the injection material are simultaneously
stopped since the injection material remaining in the hose is not
spread by a long distance.
[0021] Now, the present invention will be described in detail while
referring to examples (in which an injection material was
intermittently injected) and comparison examples (in which an
injection material was continuously injected) conducted for a
perforating processing.
[0022] In both the examples and the comparison examples, the
above-stated high accuracy blast processing apparatus was employed.
Using alumina powder having a mean particle diameter of 10 .mu.m as
an injection material, the injection material was injected to a
soda lime glass plate having a thickness of 3 mm. After 5 minutes
of the injection, the diameters of holes and the presence/absence
of damages around the holes were examined. The injection conditions
and processing results are shown in Table 1 below.
[0023] Table 1.fwdarw.ANOTHER PAPER
[0024] In Table 1, test Nos. 1 to 4 show test results conducted
under conditions that the inside diameter of the nozzle was 0.6 mm,
air pressure was 1.0 MPa and the injection quantity of the
injection material was 10 g/min.
[0025] In the test No. 3 as a comparison example shown in Table 1,
after 5 minutes of continuous injection, the depth of a hole was
0.60 mm, the diameter of the hole was 1.40 mm and a cloud-shaped
damage was generated around the hole due to the splashing of the
injection material. In the test No. 1 as an example of the present
invention, by contrast, the conditions were the same as those of
the test No. 3 except that the processing was conducted by
injecting the injection material intermittently for injection time
of 0.04 sec and stop time of 0.04 sec. The depth of a hole after 5
minutes of the injection was 1.81 mm which was about three times as
large as that in the comparison example, indicating that processing
efficiency was largely improved. Also, the diameter of the hole
after 5 minutes of the injection was 1.02 mm which was smaller than
that in the test No. 3. That is, it was possible to form a highly
accurate hole and no damage was seen around the hole.
[0026] Likewise, in the test No. 2 as the example of the present
invention, the processing was conducted by injecting the injection
material intermittently for injection time of 0.5 sec and stop time
of 0.5 sec with the other conditions set the same as those of the
test No. 3. The depth of a hole after 5 minutes of the injection
was 1.21 mm which was smaller than that in the example of the test
No. 1 but about twice as large as that in the comparison example of
the test No. 3, thereby exhibiting high processing accuracy.
Further, the diameter of the hole after 5 minutes of the injection
was 1.15 mm which was smaller than that in the example of the test
No. 1 but about twice as large as that in the comparison example of
the test No. 3, making it possible to conduct the perforating
processing without generating a damage with higher accuracy than
that of the comparison example of the test No. 3. In the test No. 4
in which the injection of the injection material for 1.05 sec and
the injection stop thereof for 1.05 sec were alternately repeated,
the depth of the hole after 5 minutes was as small as 0.75 mm, the
diameter of the hole was 1.31 mm and damage, though quite slightly,
was generated around the hole. It was, however, confirmed that the
test No. 4 was superior to the comparison example of the test No.
3.
[0027] Next, FIG. 2 shows the manners of changes in the depths of
holes in the examples of the test Nos. 1 and 2 and the comparison
example of the test No. 3 and FIG. 3 shows the manners of changes
in the diameters thereof. As can be seen from FIGS. 2 and 3, the
examples of the present invention exhibited high processing
efficiency and high processing accuracy from the initial period of
the injection compared with the comparison example.
[0028] In addition, test Nos. 5 to 6 in Table 1 show test results
conducted under the conditions that the inside diameter of the
nozzle was 1.8 mm, the mean particle diameter of the injection
material was 45 .mu.m, air pressure was 2.5 MPa and the injection
quantity of the injection material was 50 g/min. The example of the
test No. 5 in which the injection material was injected
intermittently, could attain higher processing efficiency and
higher processing accuracy than those of the comparison example of
the test No. 6 in which the injection material was continuously
injected under the same conditions as those of the test No. 5.
Further, in Table 1, test Nos. 7 to 8 show test results conducted
under the conditions that the inside diameter of the nozzle was 0.2
mm, the mean particle diameter of the injection material was 5
.mu.m, air pressure was 0.2 MPa and the injection quantity of the
injection material was 2 g/min. In the example of the test No. 7 in
which the injection material was intermittently injected, it was
possible to conduct a perforating processing to the substrate with
higher processing efficiency and higher processing accuracy than
those of the comparison example of the test No. 8 in which the
injection material was continuously injected under the same
conditions as those of the test No. 7. In the examples of test Nos.
6 and 8, damages were seen around the holes. In the examples of the
test Nos. 5 and 7, no damages were seen around the holes. It was,
therefore, confirmed that it was possible to conduct a highly
accurate blast processing by processing the substrate by
intermittently injecting the injection material without using a
mask such as a photo resist.
[0029] The high accuracy blast processing method according to the
present invention is particularly optimum for locating a nozzle at
a predetermined position and conducting a perforating processing.
However, this method is also advantageous for scanning a nozzle and
forming a large square recess. That is, by conducting intermittent
injection only right after the start of the processing and right
before the end of the processing to reduce the residual injection
material in the hose and conducting intermittent injection only for
processing the peripheral portion of the recess to prevent the
occurrence of a damage on the outer peripheral portion of the
recess, the outer peripheral portion is not damaged even if the
injection material is continuously injected to the central portion
of the recess and the injection material is removed without
remaining in the recess. It is, therefore, possible to ensure a
high speed processing. As can be seen, by appropriately combining
the intermittent injection and the continuous injection of the
injection material, it is possible to conduct a processing with
high efficiency and high accuracy without the need to use a mask.
Besides, in case of a cutting processing for the substrate, by
intermittently injecting the injection material or combining the
intermittent injection and the continuous injection, it is possible
to cut the substrate at high speed with high dimensional accuracy
without generating damage in the vicinity of the cut end face of
the substrate.
1 TABLE 1 inside mean particle injection hole hole diameter
diameter of quantity of injection conditions depth diameter of
injection air injection injection stop after 5 after 5 presence/
nozzle material pressure material time time minutes minutes absence
No. mm .mu.m Mpa g/min sec sec mm mm of damage remarks 1 0.6 10 1
10 0.04 0.04 1.81 1.02 absent example 2 0.6 10 1 10 0.5 0.5 1.21
1.15 absent example 3 0.6 10 1 10 continuous injection 0.6 1.4
present comparison 4 0.6 10 1 10 1.05 1.05 0.75 1.31 present
comparison 5 1.8 45 2.5 50 0.85 0.15 2.31 2.22 absent example 6 1.8
45 2.5 50 continuous injection 1.5 2.66 present comparison 7 0.2 5
0.2 2 0.06 0.06 0.41 0.38 absent example 8 0.2 5 0.2 2 continuous
injection 0.24 0.55 present comparison
* * * * *