JP5177609B2 - Workpiece manufacturing method - Google Patents

Description

The present invention relates a semiconductor, glass, ceramics, in the manufacture how the elemental metal or metal oxide of the single crystal and polycrystalline like brittle workpiece surface to pressurized Engineering materials.

Conventionally, as a method for precisely polishing a surface of a hard and brittle material such as a semiconductor, glass, ceramics, a single metal or a single crystal of a metal oxide with a polishing apparatus or the like, for example, a processing method as in Patent Document 1 is known. It has been.
In this processing method, means called residence time control is used, which will be further described with reference to FIG.
In FIG. 9, reference numeral 30 denotes a polishing apparatus. The polishing apparatus 30 includes a polishing processing unit including a polishing head 50 that processes the surface of the workpiece 36, and a shape measuring unit.
In this polishing apparatus, the processing amount and processing shape per unit time by a certain first polishing head are made constant, and the difference from the target processing shape is obtained based on the shape data of the workpiece measured in advance.
Then, a part that needs to be processed more is applied for a long time, and a part that needs to be processed less is applied with a short-time polishing tool, and processing is performed by a method called residence time control that changes the processing amount described above. .
At that time, the polishing tool remains in contact with the surface of the workpiece from the start to the end of the processing.
Patent Document 2 proposes a removing device that removes a film laminated on the surface of a mirror using an ion beam.
JP-A-5-57606 JP 2003-98297 A

However, the conventional processing method has the following problems.
In the case of the conventional processing method, the polishing tool or the ion beam continues to process the workpiece surface from the start to the end of the processing, so that the portion that does not need to be processed is processed. The amount increases as a whole, and the processing time increases.
At this time, if the processing speed is increased in order to shorten the processing time, the processing accuracy is lowered, and in some cases, there is a risk that the shape accuracy is worse than that before processing.

In view of the above problems, it is an object to provide a manufacturing how the workpiece can be performed at short time high-precision processing.

The present invention provides a method for manufacturing a workpiece configured as follows.
In the method for manufacturing a workpiece according to the present invention, when the workpiece is processed by irradiating the workpiece with the ion beam , processing required for processing each part of the workpiece by irradiation with the ion beam is performed. Find the time in advance,
Depending on the previously obtained processing time, the method of manufacturing a workpiece to be machined by changing the inter-irradiation Idi of the ion beam with respect to each portion of the workpiece,
A step of determining a unit dividing Saryou which the ion beam is removed per unit time,
A step of obtaining the measurement data of the surface shape of the workpiece,
From the difference between the measurement data and setting the shape data, a step of determining said and processing unwanted portions of the workpiece, the removal amount in the partial and partial to be processed, the,
The processing is unnecessary portion, the step of the ion beam irradiation so as to OFF, the obtained in advance the machining time of irradiating the ion beam from the removal amount and the unit removal amount in the portion to be machined When,
It is characterized by having.
In the method for manufacturing a workpiece of the present invention, the ion beam irradiation is turned off by a mechanical shutter.
Further, in the workpiece manufacturing method of the present invention, the ion beam irradiation is turned off by a voltage applied to an acceleration electrode of an ion beam gun that irradiates the workpiece with the ion beam. And
In the workpiece manufacturing method of the present invention, the ion beam irradiation is turned off by a voltage applied to an electrostatic deflection electrode of an ion beam gun that irradiates the workpiece with the ion beam. It is characterized by.
In the method for manufacturing a workpiece according to the present invention, the workpiece is an aspherical mirror.

According to the present invention, it is possible to realize a manufacturing how the workpiece can be performed at short time high-precision processing.

The ion beam processing method according to the embodiment of the present invention can be carried out, for example, as follows when performing the ion beam processing by applying the above-described present invention.
First, a material of the same type as the workpiece is processed using an ion beam, and a removal amount per unit time by the ion beam is obtained. Next, the surface shape of the workpiece is measured, and the removal amount corresponding to the processing amount is calculated from the difference between the measured data measured here and the set shape. Of the calculated removal amounts of each part, the removal amount of each part is calculated on the basis of the portion with the smallest removal amount.
Further, the machining time required for each part is calculated from the amount of removal per unit time determined in advance and the amount of removal of the workpiece, and machining is performed while scanning the surface of the workpiece with an ion beam.
At this time, scanning is stopped according to the processing time, and a necessary amount is removed. In addition, the part that does not need to be processed is shielded or turned off, and the removal process is not performed. By processing in this way, the processing time can be shortened while increasing the processing accuracy.
As described above, according to the present embodiment, for example, in the case where the position to be processed and the amount of removal thereof are obtained by calculation with respect to the value obtained by measuring the shape error of the workpiece, ions are only generated at the position to be removed. Irradiate the beam.
By stopping the ion beam at the position where removal processing is not required, the processing amount of the entire workpiece can be minimized, and the ion beam irradiation amount is decreased to reduce the removal rate in order to increase processing accuracy. Even in this case, the processing time can be shortened.
Furthermore, only the part to be processed is irradiated with an ion beam, and the amount of processing at that time is set small, so even if the processing accuracy varies somewhat and the processing is too much, the shape error is worse than before processing I will not let you.
When a mechanical shutter is used for the ion beam ON / OFF mechanism, the ion beam ON / OFF can be easily realized with a simple structure.
Further, according to the present embodiment, the means for turning on / off the ion beam can be realized by a configuration for turning on / off the ion extraction voltage and the acceleration voltage.
According to this, since it is not necessary to mechanically introduce the inside of the vacuum chamber, it is easy to maintain a good vacuum, and further, since ions do not hit the shutter and generate particles, contamination by the shutter material is prevented. Can be eliminated.
In addition, according to the present embodiment, the means for turning on / off the ion beam can be realized by a configuration for turning on / off the voltage applied to the electrostatic deflection electrode provided inside the ion beam gun.
According to this, since it is not necessary to mechanically introduce the inside of the vacuum chamber, it is easy to maintain a good vacuum, and since the beam is only bent sideways, the ON / OFF response of the beam is good. High stability and high accuracy when the beam is ON.

Examples of the present invention will be described below.
[Example 1]
Example 1 of the present invention is by applying the configuration of the present invention to constitute a preparation how the workpiece.
Figure 1 shows a diagram for explaining a manufacturing how the workpiece in this embodiment. In FIG. 1, reference numeral 1001 denotes a vacuum chamber, which is maintained at a pressure of about 5 × 10 ⁻⁴ Pa by an exhaust device (not shown).
Reference numeral 1002 denotes a Kaufman-type ion beam gun, which is connected to an Ar gas pipe (not shown). By flowing a current through an internal filament while flowing an appropriate amount of gas, thermoelectrons are generated to ionize the Ar gas. Yes.
In addition, an ion extraction electrode and an acceleration electrode are installed inside, and a lead wire (not shown) is connected to each. These conductors are led out of the vacuum chamber and connected to a high voltage power source. These high-voltage power supplies apply voltages to the extraction electrode and the acceleration electrode, respectively.

An electrostatic lens is installed inside the ion beam gun 1002. Each of these lens electrodes is connected to the outside of the vacuum chamber by a lead wire (not shown) so that a high voltage can be applied.
Here, a unit removal amount (hereinafter referred to as a unit removal shape) obtained by the ion beam is obtained.
The ion beam unit removal shape is a removal depression obtained by performing processing for a certain period of time under the same ion beam gun and irradiation conditions as used in actual processing on a test piece made of the same material as the surface to be processed in advance. Is obtained by measuring the shape and converting it per unit time.
In addition, since removal processing using an ion beam is proportional to the ion current value if the beam energy is the same, if the distribution of the ion current density is measured and adjusted to a desired ion beam profile, the unit removal shape measurement for each processing is performed. It is unnecessary.

  Further, 1003 is an ion beam, 1004 is a shutter, 1007 is a Faraday cup, 1008 is a workpiece, 1009 is a fixed jig, and 1011 is a 5-axis stage. The workpiece 1008 is a convex spherical mirror made of synthetic quartz and having an outer diameter of 200 mm and a radius of curvature of 400 mm, and is fixed to the 5-axis stage 1011 by a fixing jig 1009.

The Faraday cup 1007 is connected to a lead wire (not shown), and the lead wire is drawn to the outside of the vacuum chamber so that the current value of the ion beam can be measured outside the vacuum chamber.
Since the opening of the Faraday cup 1007 is as small as φ0.1 mm, the current density distribution of the ion beam can be measured by measuring the stage 1011 while moving it in the XY direction.
Here, the extraction voltage of the ion beam gun was 1 kV, the acceleration voltage was 6 kV, the total ion current value was 10 μA, and the beam diameter was adjusted to 3 mm as shown in FIG.

Below, the operation | movement flow at the time of the process in a present Example is demonstrated.
First, the three-dimensional surface shape of the pre-processed workpiece 1008 is measured with high accuracy to obtain surface shape data. The measuring device at this time was a probe contact type measuring device and measured at a pitch of 1 mm.
Next, the measurement data and the design shape data are compared to obtain a difference and set as a removed shape. The removal shape and the unit removal shape by the ion beam obtained in advance were calculated and converted into the machining time at each machining point.
At this time, the region where the machining amount was zero was programmed to turn off the ion beam.

FIG. 3 shows a locus when scanning on the workpiece 1008, and the workpiece is processed along the line 1033 while irradiating with an ion beam.
At this time, the movement of the workpiece is stopped for a long time at the portion where the removal amount is large, the movement of the workpiece is stopped for a short time at the portion where the removal amount is small, and the ion beam irradiation is performed at the portion where the removal is unnecessary. Stop and move the workpiece.

FIG. 4 is a diagram showing a part of the workpiece for explaining the removal processing.
1041 in FIG. 4 is the moving direction of the workpiece 1049. Reference numeral 1042 denotes an ion beam gun, and reference numeral 1043 denotes an ion beam.
At the processing point 1045 during ion beam irradiation, the movement of the workpiece is stopped for 3 seconds, and at the processing point 1046, the movement of the workpiece is stopped for 5 seconds.
Next, when the processing progresses gradually and the ion beam comes to the position of the processing end point 1047, the shutter 1044 installed near the ion exit of the ion beam gun is operated to stop the ion beam.

Since the machining is not performed while the beam is stopped, the workpiece can be quickly moved to the next machining start point 1048. When the ion beam reaches the next processing start point 1048, irradiation of the ion beam is started, and the processing is continued by controlling the processing time at each point.
When processing is performed in this way, efficient processing can be performed with a minimum processing amount.
In the surface shape measurement before ion beam processing, the maximum difference from the set value was 20 nm. After that, when processed by the ion beam processing apparatus of the present invention, the spherical mirror had an error within 1.5 nm with respect to the set shape.

[Example 2]
Example 2 of the present invention is by applying the configuration of the present invention to constitute a preparation how the workpiece.
Figure 5 shows a diagram for explaining a manufacturing how the workpiece in this embodiment. In FIG. 5, reference numeral 2001 denotes a vacuum chamber, which is maintained at a pressure of about 5 × 10 ⁻⁴ Pa by an exhaust device (not shown).
Reference numeral 2002 denotes an ion beam gun having an RF type ion source. FIG. 6 shows the internal structure of the ion beam gun.
An ionization chamber 2062 is connected to a pipe (not shown) and supplied with Ar gas.
Also, an RF power source (not shown) is connected, and Ar gas is ionized by the RF power.

Reference numeral 2003 denotes an ion beam, 2007 denotes a Faraday cup, 2008 denotes a workpiece, 2009 denotes a fixed jig, and 2011 denotes a 5-axis stage.
The workpiece 2008 is a convex aspherical mirror made of low-expansion glass with an outer diameter of 180 mm and a curvature radius of about 300 mm, and is fixed to the 5-axis stage 2011 by a fixing jig 2009.
The Faraday cup 2007 is connected to a lead wire (not shown), and the lead wire is drawn out to the outside of the vacuum chamber so that the current value of the ion beam can be measured outside the vacuum chamber.
Since the opening of the Faraday cup 2007 is as small as 0.1 mm, the current profile of the ion beam can be measured by measuring the stage 2011 while moving it in the XY direction.

2063 is a component called an extraction electrode, and 2064 is an acceleration electrode. A high voltage is introduced from a high voltage power source installed outside a vacuum chamber (not shown), and Ar particles converted into ions in the ionization chamber are extracted and accelerated.
Reference numeral 2065 denotes an electrostatic lens, which has a role of converging accelerated ions to narrow the ion beam at a predetermined position. The unit removal shape when the workpiece is irradiated using such an ion beam gun is obtained in the same manner as in the first embodiment.
Here, the extraction voltage of the ion beam gun was 1 kV, the acceleration voltage was 3 kV, the total ion current value was 30 μA, and the beam diameter was adjusted to 5 mm with a half-value width by an electrostatic lens.

Below, the operation | movement flow at the time of the process in a present Example is demonstrated.
First, the three-dimensional surface shape of the pre-processed workpiece 2008 is measured with high accuracy to obtain surface shape data. The measuring instrument at this time was a probe contact type measuring instrument and measured at a pitch of 0.5 mm.
Next, the measurement data and the design shape data are compared to obtain a difference and set as a removed shape. The removal shape and the unit removal shape by the ion beam obtained in advance were calculated and converted into the machining time at each machining point. At this time, the region where the machining amount is zero is programmed to turn off the ion beam.
Similar to the first embodiment, the workpiece 2008 is processed while being scanned with an ion beam.
At this time, the movement of the workpiece was stopped for a long time in the portion where the removal amount was large, and the movement stop of the workpiece was shortened in the portion where the removal amount was small.
Further, the workpiece was moved by stopping the irradiation of the ion beam at the portion where the removal was unnecessary. When the ion beam irradiation was stopped, the extraction voltage and the acceleration voltage were set to zero.

When the ion beam is turned on / off in this manner, it is not necessary to mechanically introduce the inside of the vacuum chamber, so that it is easy to maintain a good vacuum.
Furthermore, since ions do not hit the shutter and generate particles, contamination by the shutter material can be eliminated and clean processing can be performed.
Further, when processing is performed in this manner, efficient processing can be performed with a minimum processing amount.
In the surface shape measurement before ion beam processing, the maximum difference from the set value was 25 nm. After that, when processed by the ion beam processing apparatus of the present invention, the aspherical mirror as the workpiece had an error within 2 nm with respect to the set shape.

[Example 3]
Examples of the present invention 3 is a by applying the configuration of the present invention to constitute a preparation how the workpiece.
Figure 7 shows a diagram for explaining a manufacturing how the workpiece in this embodiment. In FIG. 7, reference numeral 3001 denotes a vacuum chamber which is maintained at a pressure of about 5 × 10 ⁻⁴ Pa by an exhaust device (not shown).
Reference numeral 3002 denotes an ion beam gun having a microwave type ion source, and FIG.
In FIG. 8, reference numeral 3062 denotes an ionization chamber in which Ar gas (not shown) is piped, Ar gas is flowed at 0.2 sccm, and a microwave is guided from outside the ionization chamber to the ionization chamber by a waveguide (not shown) to generate plasma. The gas is ionized. Reference numeral 3063 denotes an ion extraction electrode, and 3064 denotes an acceleration electrode, to which conductive wires (not shown) are connected. These conductors are led out of the vacuum chamber and connected to a high voltage power source.
These high-voltage power supplies apply voltages to the extraction electrode and the acceleration electrode, respectively.
Reference numeral 3065 denotes an electrostatic lens, which is composed of three cylindrical electrodes, and has a role of converging accelerated ions to narrow the ion beam at a predetermined position.
Reference numeral 3066 denotes an electrostatic deflection electrode which has a pair of opposed structures, and is connected to a lead wire (not shown) so that a high voltage can be applied.
When no voltage is applied, the ion beam traveling as indicated by 3067 advances when the voltage is applied as indicated by 3068 and is not irradiated from the exit.
A unit removal shape obtained by such an ion beam gun is obtained in the same manner as in the first embodiment.

Reference numeral 3003 denotes an ion beam, 3007 denotes a Faraday cup, 3008 denotes a workpiece, 3009 denotes a fixed jig, and 3011 denotes a 5-axis stage.
The workpiece 3008 is a concave aspherical mirror made of low-expansion glass having an outer diameter of 200 mm and a radius of curvature of about 550 mm, and is fixed to a 5-axis stage by a fixing jig 3009.
The Faraday cup 3007 is connected to a lead wire (not shown), the lead wire is drawn out to the outside of the vacuum chamber, and the current value of the ion beam can be measured outside the vacuum chamber.
Since the opening of the Faraday cup 3007 is as small as φ0.1 mm, the current density distribution of the ion beam can be measured by measuring the stage 3011 while moving it in the XY direction.
Here, the extraction voltage of the ion beam gun was 1 kV, the acceleration voltage was 10 kV, the total ion current value was 30 μA, and the beam diameter was adjusted to 1 mm with a half-value width by an electrostatic lens.

Below, the operation | movement flow at the time of the process in a present Example is demonstrated.
First, the three-dimensional surface shape of the pre-processed workpiece 3008 is measured with high accuracy to obtain surface shape data. The measuring instrument at this time was a probe contact type measuring instrument and measured at a pitch of 0.25 mm.
Next, the measurement data and the design shape data are compared to obtain a difference and set as a removed shape.
The removal shape and the unit removal shape by the ion beam obtained in advance were calculated and converted into the machining time at each machining point.
At this time, the region where the machining amount is zero is programmed to turn off the ion beam.

Similar to the first embodiment, the workpiece 3008 is processed while being scanned with an ion beam.
At this time, the movement of the workpiece was stopped for a long time in the portion where the removal amount was large, and the movement stop of the workpiece was shortened in the portion where the removal amount was small.
Furthermore, the ion beam irradiation is stopped at a portion where removal is not necessary, and the workpiece is moved.
In order to stop the irradiation of the ion beam, a voltage was applied to the electrostatic deflection electrode provided immediately after the focusing lens of the ion beam gun, and the beam was bent and applied to the shielding plate so that the ion beam was not emitted.

When the ion beam is turned on / off in this manner, it is not necessary to mechanically introduce the inside of the vacuum chamber, so that it is easy to maintain a good vacuum.
Further, even when the ion energy is high, the ion beam is only bent in the lateral direction, so that the ON / OFF responsiveness of the beam is good, and since the stability when the beam is ON is particularly good, highly accurate processing can be performed.
Further, when processing is performed in this manner, efficient processing can be performed with a minimum processing amount.
In the surface shape measurement before ion beam processing, the maximum difference from the set value was 30 nm. After that, when processed by the ion beam processing apparatus of the present invention, the aspherical mirror as the workpiece had an error within 2 nm with respect to the set shape.

Is a diagram for explaining a manufacturing how the workpiece according to the first embodiment of the present invention. It is a figure explaining the profile of the ion beam which concerns on Example 1 of this invention. It is a figure explaining the scanning method at the time of ion beam processing concerning Example 1 of the present invention. It is a figure explaining the ion beam processing method which concerns on Example 1 of this invention. Is a diagram for explaining a manufacturing how the workpiece according to the second embodiment of the present invention. It is a figure explaining the structure of the ion beam gun which concerns on Example 2 of this invention. Is a diagram for explaining a manufacturing how the workpiece according to the third embodiment of the present invention. It is a figure explaining the structure of the ion beam gun which concerns on Example 3 of this invention. It is a figure explaining the prior art.

Explanation of symbols

1001, 2001, 3001: Vacuum chambers 1002, 2002, 3002: Ion beam guns 1003, 2003, 3003: Ion beam 1004: Shutters 1007, 2007, 3007: Faraday cups 1008, 2008, 3008: Workpieces 1009, 2009, 3009: Fixed jigs 1011, 2111, 3011: 5-axis stage 1033: ion beam scan line 1041: workpiece moving direction 1042: ion beam gun 1043: ion beam 1044: shutter 1045, processing point 1047: processing end point 1048: processing start Point 1049: Workpiece 1050: Processing target line 2061, 3061: Ion beam gun 2062, 3062: Ionization chamber 2063, 3063: Extraction electrode 2064, 3064: Accelerating power 2065,3065: electrostatic lens 2066,3067,3068: ion beam 3066: electrostatic deflection electrode

Claims (5)

When processing the workpiece by irradiating the workpiece with an ion beam, a processing time required for processing each part of the workpiece by the irradiation of the ion beam is obtained in advance.
Depending on the previously obtained processing time, the method of manufacturing a workpiece to be machined by changing the inter-irradiation Idi of the ion beam with respect to each portion of the workpiece,
A step of determining a unit dividing Saryou which the ion beam is removed per unit time,
A step of obtaining the measurement data of the surface shape of the workpiece,
From the difference between the measurement data and setting the shape data, a step of determining said and processing unwanted portions of the workpiece, the removal amount in the partial and partial to be processed, the,
The processing is unnecessary portion, the step of the ion beam irradiation so as to OFF, the obtained in advance the machining time of irradiating the ion beam from the removal amount and the unit removal amount in the portion to be machined When,
A method for producing a workpiece, characterized by comprising:   The method of manufacturing a workpiece according to claim 1, wherein the irradiation of the ion beam is turned off by a mechanical shutter.   2. The workpiece production according to claim 1, wherein the ion beam irradiation is turned off by a voltage applied to an acceleration electrode of an ion beam gun that irradiates the workpiece with the ion beam. Method.     2. The workpiece according to claim 1, wherein the ion beam irradiation is turned off by a voltage applied to an electrostatic deflection electrode of an ion beam gun that irradiates the workpiece with the ion beam. Manufacturing method.   The method of manufacturing a workpiece according to any one of claims 1 to 4, wherein the workpiece is an aspherical mirror.

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