SU847404A1 - Trepanning drill - Google Patents

Description

one

The invention relates to the manufacture of semiconductor devices and can be used in the manufacture of semiconductor wafers of plates and crystals.

A known ultrasonic tool for cutting round semiconductor plates and. crystals, on the end surface of the casing of which metal L13 tubes are drunk

The disadvantage of this tool is its limited technological capabilities: it allows you to cut the plates in the form of disks, but with its help it is impossible to simultaneously chamfer the contour of the disk, which is necessary for. improving the quality of manufacturing plates and crystals.

Also known is a combined tool for machining a hole in products while simultaneously chamfering the edge of the hole. The combination tool comprises a housing, a countersink and knives for chamfering L2j.

However, this tool cannot be used when cutting semiconductor wafers and crystals, since its use requires

pre-have a hole in the workpiece.

The closest in technical essence to the invention is an annular drill bit comprising a body and a cutting edge. The cutting edge is located on the end surface of the body and is made in the form of a thin cylindrical tube equal to a height of 3J.

However, this annular drill also does not allow to chamfer on them simultaneously with the cutting of the plates and crystals.

The purpose of the invention is to expand the technological capabilities of a ring drill.

This goal is achieved by the fact that, in a circular drill, containing Kdpnyc and a cutting edge, the cutting edge is designed as a segment of a spiral of variable height, which decreases uniformly from the outer to the inner end of the spiral.

In addition, in order to increase the wear resistance of the annular drill, the cutting edge is made in the form of two or more helix segments symmetrically arranged with respect to

each other with an offset of 180, 120 ° or 90 °.

FIG. 1 schematically shows a circular drill with one segment of a spiral, a general view; in fig. 2 - scan of the segment of the spiral; in fig. 3 is a cutting edge consisting of three segments of a helix, plan view.

The annular drill bit comprises a housing 1 and a cutting edge 2 located on its end surface, made in the form of a spiral segment of variable height, decreasing uniformly from the outer to the inner end of the spiral, while the distance between the outer and inner ends of the spiral is determined by the chamfer width (its projection) .

As a cutting edge 2, an abrasive-containing tape was applied, along which the cut was made at an angle / b determined by the formula (Fig. 2):

 tgol.

tgfb

where 6 is the width of the chamfer, mm (not shown); 1 - cut length

tapes, mm;

oL - chamfer angle, degree (not shown).

FIG. , 3 The cutting edge 2 is made in the form of three segments of a helix, arranged symmetrically relative to each other and offset at an angle of 120 °.

The ring drill processing is carried out as follows.

I put the silicon plates with the finished semiconductor devices with shellac on the glass substrate, which is fixed on the desktop of the drilling machine. The annular drill is then secured by the body 1 in the cylinder of the drilling machine and is rotated (in the direction of decreasing the height of the cutting edge) with simultaneous feeding of the circular drill under load. Towards the silicon wafer to be machined. In this case, first, the cutting edge 2 acts on the silicon wafer with its highest part. This point of impact during the rotation of the ring drill continuously describes a circle with a diameter equal to the diameter of the cut-out crystal, up to the complete cutting of the silicon wafer.

All other areas (points) of the cutting edge sequentially interact with the silicon wafer as the edge deepens. This smelt removes the surface layer of silicon along the edge of the crystal being cut to form a chamfer. Thus, the chamfering operation is completed simultaneously with the completion of the operation of cutting the crystal from the silicon wafer.

When using a core drill with several helix pieces, the cutting edge has an increased wear resistance.

Claims (3)

1. Ring drill, mainly for drilling fragile materials, comprising a body and a cutting edge, characterized in that, in order to expand technological capabilities, the cutting edge is designed as a segment of a spiral of variable height, uniformly decreasing from the outer to the inner end of the spiral. 2. A drill according to claim 1, characterized in that, in order to increase its wear resistance, the cutting edge is made in the form of two or more helix pieces located symmetrically relative to each other with an angle shift of 180, 120 ° or 90 °. Sources of information taken into account in the examination 1. The patent of Germany No. 1614554, cl. H 01 L 21/302, 1977. 2. USSR author's certificate number 122387, cl. B 23 B 51/08, 1958. 3. USSR author's certificate number 517412, cl. B 23 B 51/08, 1976 (prototype).