Patent Application
20060101977
The present invention relates to a diamond scriber, and particularly a diamond scriber characterized by a knife-edge shape.
Conventionally there have been diamond scribers of which the ridge line connecting the toe point and heel point is on the (111) face and the angle between the faces that meet at this ridge line is selected between 140° and 150° (see Japanese Patent Laid-Open Publication No. 47-40393).
Further, there have been eight-point diamond scribers which has the inclination angle (θ) of which the ridge line connecting the toe point and the heel point relative to the horizontal face is 55° or an angle near that (See Japanese Patent Laid-Open Publication No. 49-54987).
Moreover, there have been eight-point diamond scribers in which the delta face of which the heel point is the apex is formed on the (111) face in the Miller notation, the angle (β) of the ridge line connecting the toe point and the heel point relative to the delta face is 15° or an angle near that, and the delta face angle (α) is 46° or an angle near that (see Japanese Patent Laid-Open Publication No. 49-54988).
Further, there are scriber points of hard materials with four-way symmetry, in which there is a horizontal tip portion, a ridge line that extends from one apex of the horizontal tip portion, and a side portion that gradually spreads in the direction of the base portion with the other end of the ridge line as the apex, and in which ½ to ¼ of the length of the ridge line has been scraped from the other end in the direction of the horizontal tip portion (see Japanese Utility Model Laid-Open Publication No. 56-155452).
Nevertheless, the diamond scribers introduced in the above-described publications all have problems that after scribing repeatedly, the depth of the slot generated by scribing becomes shallow and the width of the slot spreads by abrasion of the edge.
The present invention has been devised in view of the above-described problem points, and an object of the present invention is to provide a diamond scriber that can maintain an excellent scribe line for a longer period.
According to the present invitation, there is provided a diamond scriber, in which an apex region of a triangular pyramid, which is a toe and/or heel of a diamond particle, is formed to a knife-edge shape along a ridge line connecting the toe and heel.
Accordingly, since the edge of the diamond scriber is formed to a knife-edge shape, it is possible to limit the spread of scribe line width.
According to a preferred embodiment, a width of the knife-edge shape is in a range from 5 μm to 15 μm.
Accordingly, it is possible to draw a scribe line with a narrow width between 5 μm and 15 μm, even with repeated scribing.
According to another preferred embodiment, a height of the knife-edge shape is at least 2 μm.
Accordingly, it is possible to prolong the lifetime of the diamond scriber, in proportion to the height of the knife-edge shape.
According to another preferred embodiment, the knife-edge shape is formed by scraping two ridges except said ridge line of the triangular pyramid along said ridge line.
Accordingly, the appropriate knife-edge shape can be formed properly.
A diamond particle 1 illustrated in
The knife-edge shaped toe, which is the major part of the present invention, is explained here on the basis of
As illustrated in
Now, because the appropriate dimensions of the knife-edge shape width L1 and height H vary depending on the wafer material, the dimensions of the knife-edge shape width L1 and height H in the present invention are not limited to the dimensions above. Further, the diamond scriber of the present invention is not limited to a four-point scriber or an eight-point scriber; the present invention can be applied to any diamond scriber in which the edge has a triangular pyramid, which has the toe as its apex.
Next, the inscribing of a sapphire wafer using the diamond scriber illustrated in
[Test Case]
A sapphire wafer was inscribed repeatedly using the diamond scriber illustrated in
Because the edge of the diamond scriber illustrated in the test case is machined into a knife-edge shape, it is possible to draw a fine scribe line of 8.0 μm or less in width until the height H wears out to 2.97 μm. In other words, it is possible to repeatedly pull a fine scribe line of 8.0 μm or less in width, and also the lifetime of the diamond scriber can be prolonged.
[Control Case]
A sapphire wafer was inscribed repeatedly using an ordinary diamond scriber not machined into a knife-edge shape, until a good scribe line was no longer drawn, and the worn-out portion of the edge was measured. The dimensions of the edge worn-out portion 11j at the limit of usability, as illustrated in
Because the knife edge of the diamond scriber illustrated in the control case is not machined into a knife-edge shape and remains in the shape of a triangular pyramid, if it is used until the height H of the worn-out portion reaches 1.49 μm, the worn-out portion causes the edge to spread toward the base of the triangular pyramid, and it becomes impossible to draw a fine scribe line of 8.5 μm or less in width.
As stated above, when the height H of the worn-out portion of the test case is compared with the height H of the worn-out portion of the control case, it is clear that the diamond scriber of the test case has a longer lifetime, and a scribe line with good quality can be made longer.
When inscribing sapphire wafers using the diamond scriber of the present invention, it is possible to maintain a scribe line with good quality for a longer period. In other words, it is possible to prolong the lifetime of the diamond scriber.
