JP2007044729A - Method for machining flat work - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a time and cost for machining a difficult-to-machine material such as a silicon substrate. <P>SOLUTION: Through-holes 31a, 31b are made from the surface side of a silicon substrate 3 (a workpiece W) through the rear surface side thereof on predetermined positions by a laser beam. A 1st XY coordinate system for machining the surface side is set based on the image data obtained by a camera 12 which captures the images of reference holes 30a, 30b formed at the rear side surface of the through-holes 31a, 31b, and the surface side is machined. After machining of the surface side is completed, a 2nd XY coordinate system is set based on the image data obtained by the camera 12 which captures the images of the reference holes 30a, 30b from the upper surface side of the workpiece W that is reversed around the Y axis, and the portions, of which the surface sides are machined, are machined while making the coordinate values on an axis, around which the workpiece W is reversed after machining of the surface side, mirror image values and leaving the coordinate values on the other axis as they are. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for processing difficult-to-cut materials such as a silicon substrate.

For example, in a silicon substrate, a hole may be formed in the silicon substrate, and a linear terminal portion of a circuit element may be inserted and fixed in the formed hole. Since a silicon substrate is a difficult-to-cut material, for example, when a hole with a diameter of 0.7 mm is processed on a 1 mm silicon substrate, the number of holes that can be processed with one drill is several. Therefore, since it is not a good idea to form such holes by drilling, the reference hole (hereinafter referred to as “reference hole”) is drilled and other holes are formed based on the processed reference hole. It was processed by dry etching. In order to improve the etching rate during this processing, various etching gases have been studied (Patent Document 1).
Japanese Patent Laid-Open No. 9-7996

  In recent years, the use of a silicon substrate having a large plate thickness has increased, and accordingly, an improvement in processing speed is desired. Therefore, in the invention described in Patent Document 1, an edging gas has been studied in order to improve the etching rate. However, the selection of the edging gas alone cannot cope with the improvement of the processing speed currently aimed at.

  The present invention has been made in view of such a background, and its purpose is a flat plate capable of reducing the processing cost and reducing the processing cost even for difficult-to-cut materials such as a silicon substrate substrate. It is in providing the processing method of a workpiece.

  In order to solve the above-mentioned problems, the present invention provides a method for processing a flat workpiece, wherein at least one hole penetrating from the front surface (one surface) side to the back surface (other surface) is formed by a laser at a predetermined position of the flat workpiece. 1st XY processing coordinate for processing and imaging the hole shape in the said back surface (other surface) of the said through hole from the said surface (one surface) side, and processing the said surface (one surface) side from the acquired imaging data Determine the system, perform the processing on the surface (one surface) side by the determined processing coordinate system, after the processing of the surface (one surface) side is finished, the plate-like workpiece is inverted around the Y axis or the X axis, The hole shape of the through hole is imaged from the upper surface (other surface) side of the inverted flat workpiece, a second XY processing coordinate system is defined based on the obtained imaging data, and the surface (one surface) side is defined. Coordinates for the reversed axis when machining Was a mirror image values, by processing a portion obtained by processing the surface (one surface) side by the coordinate values for the other axes in the same, and wherein the processing the same point of the flat workpiece from both sides.

  According to the present invention, since drilling is not performed, the total machining cost can be reduced and the time required for machining can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall configuration diagram of a flat workpiece processing apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of a main part of an XY table portion.

  As shown in FIG. 2, the silicon substrate 3 is sandwiched between the first jigs 20 a and 20 b and the second jigs 21 a and 21 b, and is integrated by bolts 22. Hereinafter, the silicon substrate 3, the first jigs 20 a and 20 b, and the second jigs 21 a and 21 b are collectively referred to as “work W”.

  The height l2 of the second jigs 21a and 21b is formed to be equal to the distance l1 from the lower surface of the silicon substrate 3 to the upper surfaces of the first jigs 20a and 20b.

  The workpiece W is fixed on the XY table 4 with bolts 23 so that the end portion is in contact with the side surface 24 a of the guide 24. A side surface 24a of the guide 24 is fixed on the XY table 4 so as to be parallel to the X axis. The XY table 4 is movable in the X direction and the Y direction.

  A light 25 is disposed in the space 4 a provided in the XY table 4. A camera 12 and an fθ lens 1 are disposed at a position facing the XY table 4. The camera 12 is positioned at a height h from the upper surfaces of the second jigs 21a and 21b that are in focus on the upper surfaces of the second jigs 21a and 21b.

Next, a processing procedure will be described.
3A and 3B are explanatory views of the reference hole in the present embodiment. FIG. 3A is a plan view of the reference hole portion, FIG. 3B is a front sectional view in the vicinity of the reference hole, and FIG. It is a bottom view of (a). FIG. 4 is an explanatory diagram of a processing procedure in the present embodiment, where FIG. 4A shows the case of the front side and FIG. 4B shows the case of the back side.

  When the holes 31a and 31b are processed at predetermined positions of the workpiece W by a laser, the formed holes are tapered holes having a diameter on the incident side larger than a diameter on the exit side. In addition, the cross section of the hole is rarely a perfect circle. Therefore, the light 25 is turned on using the holes formed on the back surface side as the reference holes 30a and 30b, and images are taken by the camera 12. Then, as shown in FIG. 4A, the average coordinates of the maximum and minimum values of the X coordinate of the reference hole 30a are set as the X coordinate of the center O1 of the reference hole 30a, and the average coordinates of the maximum and minimum values of the Y coordinate are set. The Y coordinate of the center O1 of the reference hole 30a is assumed. Similarly, the X coordinate and Y coordinate of the center O2 of the reference hole 30b are determined. Further, an angle α with respect to the X axis of the straight line O1-O2 is obtained.

  Next, a laser is irradiated to a designated position on the surface side (upper surface in FIG. 2) with the center O1 as the processing origin, and the surface silicon dioxide (silicon dioxide layer) is removed. Usually, if the depth of the hole (processed hole in FIG. 2) is about 5 μm from the surface, the silicon dioxide layer on the surface can be removed and the silicon layer can be exposed. In FIG. 2, the processing hole on the front surface side (solid line) indicates a processed state, and the processing hole on the back surface side (two-dot chain line) indicates a state before processing.

  When the surface processing is completed, the workpiece W is reversed around the Y axis and fixed to the XY table 4. Next, the light 25 is turned on, the reference holes 30a and 30b are imaged by the camera 12, and the coordinates of the center O1 and the center O2 are obtained in the same manner as described above. Then, it is confirmed that the angle of the straight line O1-O2 with respect to the X axis is −α, and processing is performed with the X coordinate when the surface side is processed with the center O1 as the origin as a negative value (with a mirror image value). That is, for example, when processing is performed at the point Qs (x, y) on the surface side, the position of the point Qb (−x, y) (the position that becomes a mirror image) is processed. That is, processing is performed at the point Qb on the surface opposite to the point Qs. As a result, when the through hole is formed by performing dry etching from both sides of the silicon substrate 3, the axis of the through hole can be made substantially coaxial.

  Thus, since the workpiece | work from which the silicon dioxide of both surfaces was removed can perform dry etching from both surfaces, an etching rate can be doubled conventionally.

  Further, since the silicon dioxide on the surface is removed by the laser, the processing speed can be improved as compared with the case of removing the silicon dioxide by the conventional dry etching.

  In this embodiment, since the height of the reference hole from the upper surface of the table when the workpiece W is reversed does not change, the work of focusing the camera is unnecessary, so that the work efficiency can be improved.

  When the workpiece W is reversed, if the angle of the straight line O1-O2 with respect to the X axis is not −α, the workpiece W may be fixed again or may be processed by coordinate conversion.

  Further, although two reference holes are provided, one reference hole may be used.

Next, a laser irradiation procedure will be described.
In FIG. 1, a laser oscillator 8 outputs a pulsed UV laser. The external shape of the laser beam 2 emitted from the laser oscillator 8 is shaped by the aperture 9, reflected by the galvanometer mirrors 6 and 7, incident on the fθ lens 1, condensed by the fθ lens 1, and disposed on the XY table 4. The surface of the workpiece W is processed. The laser beam 2 can be moved in the Y direction on the workpiece W by rotating the galvanometer mirror 6, and the laser beam 2 can be moved in the X direction on the workpiece W by rotating the galvanometer mirror 7.

  The size of the processing region 11 (galvano scanning region) determined by the galvanometer mirrors 6 and 7 and the fθ lens 1 is about 50 mm × 50 mm. When the processing of the hole in one processing region 11 is completed, the XY table 4 is moved and the next processing region 11 is positioned with respect to the fθ lens 1. Thereafter, the above operation is repeated until the machining of the entire work W is completed. The control device 13 controls the galvanometer mirrors 6 and 7, the laser oscillator 8, and the camera 12.

  In the above-described embodiment, the silicon dioxide layer is removed by laser, but a through hole may be formed by irradiating laser from one side and the other side. If it does in this way, the hole diameter of a center part can be made into the hole diameter close | similar to an entrance diameter.

  Moreover, if the laser irradiation part is provided on both the one surface side and the other surface side, and processing is performed from both sides based on the reference hole, the processing speed can be further improved.

1 is an overall configuration diagram of a flat work processing apparatus suitable for applying the present invention. It is a principal part expanded sectional view of the XY table part in this invention. It is explanatory drawing of the reference | standard hole in this invention. It is explanatory drawing of the process sequence in this invention.

Explanation of symbols

3 Silicon substrate (work W)
12 Camera 30a, 30b Reference hole 31a, 31b Through hole

Claims (3)

Processing at least one hole penetrating from one side to the other side with a laser at a predetermined position of the flat workpiece,
Image the hole shape in the other surface of the through hole from the one surface side,
A first XY processing coordinate system for processing the one surface side is determined from the obtained imaging data,
Processing on the one surface side by the determined processing coordinate system,
After the processing on the one surface side is finished, the flat workpiece is inverted around the Y axis or the X axis,
Image the hole shape of the through hole from the other surface side of the inverted flat plate workpiece,
Based on the obtained imaging data, a second XY processing coordinate system is defined,
A coordinate value related to the inverted axis when processing the one surface side is set as a mirror image value, and the same position of the flat work is processed by processing the one surface side with the same coordinate value regarding the other axis. A processing method of a flat work characterized by processing from both sides.   The flat plate workpiece processing method according to claim 1, wherein the flat plate workpiece is a silicon substrate.   3. The flat workpiece processing method according to claim 2, wherein the processing is laser irradiation for removing a silicon dioxide layer on the surface of the silicon substrate.

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