JPH0469530B2 - - Google Patents

Description

[Detailed Description of the Invention] <Field of Application> This invention is applicable to cutting ingots of silicon or the like, which are raw materials for manufacturing semiconductor devices, into sections using a rotating blade, or when slicing semiconductor wafers from ingots. This invention relates to an ingot cutting device.

<Prior art> Silicon and other ingots used in semiconductor devices are made of brittle material, so if one side is held or pressed and cut with a blade, the weight of the cut piece on the cutting side and the cutting blade will be reduced in the final area of cutting. The stress load on the uncut portion increases due to adhesion to the blade, etc., and it is likely that the blade will break off due to a so-called cracking state and chipping before the cutting by the blade is completed.

For example, in the process of pulling and manufacturing silicon single crystals, the structure, physical properties, etc. differ depending on the region at the growth interface, so in order to use the optimal region for the semiconductor to be obtained, sample cutting or section cutting is required. It is necessary to do the following. However, since ingots are expensive, it is obvious that the smaller the cutting loss, the better; however, chips as described above are likely to occur when cutting into sections, and due to these chips, the subsequent wafer slices are cut by the depth of the chip. This would be extremely uneconomical.

In addition, when wafers are obtained by slicing them from ingots, the slice thickness is generally several hundred microns, so in the final region of slicing, the surface tension of the cutting fluid, the weight of the wafer, the effect of the wafer recovery device during recovery, etc. As a result, the above-mentioned chipping is likely to occur, and therefore, the productivity is significantly reduced due to the chipping at the outer periphery where the largest number of semiconductor elements can be obtained from a single wafer.

Therefore, we aim to prevent this problem as much as possible and improve productivity.
The following measures are generally taken to improve yield.

That is, one of them is slice-based attachment.
A waste material made of carbon or the like (hereinafter referred to as the slice base) is attached to a part of the side surface of the ingot in the longitudinal direction by gluing or the like, and cutting is performed from the side facing the slice base, and the slice base is cut at the end. (For example, see Japanese Patent Application Laid-Open No. 61-65749).

According to this method, the problem of loss of ingots and wafers is temporarily resolved, but it requires work such as preparing the slice base in advance, attaching it, and removing it from the wafer after cutting. Therefore, it is necessary to select materials that do not have any negative effects.

Therefore, although the attachment of slice bases has some advantages in preventing loss of ingots and wafers, the presence of slice bases that are ultimately discarded is something that needs improvement in this respect. Ta.

Next, as the second means, in addition to the rotation of the blade, there is also rotation of the ingot, especially regarding wafer slicing (see, for example, Japanese Patent Laid-Open No. 147312/1983). When the ingot is rotated, it is cut from the periphery toward the center, so there is no loss at the outer periphery, where productivity is high, and there is no need for a slicing base, which is an advantage. In terms of device performance, even higher precision and functionality will be required.

That is, when recovering sliced wafers,
When the above-mentioned slicing base is attached, the wafer may be gripped or held by suction with a vacuum chuck at the stage of cutting the base, but in the case of ingot rotation, the wafer must be gripped or suctioned at least immediately before the cutting is completed. If this happens, the wafer may shake or twist due to the suction, etc., resulting in a chip in the center.To solve these problems, for example, synchronization and concentric rotation of the gripping or suction mechanism, and skillful contact with the wafer. It is necessary to measure the concentricity with the chuck side (face), especially when there is a shape defect such as the flatness of the ingot end face or the perpendicularity to the machine rotation axis, as in the case of the first cutting. It is difficult to rotate, and from this point of view, it is difficult to realize and maintain accuracy and functionality of the device as a whole. In addition, in the case of this ingot rotation, a so-called "belly button" protrusion is likely to occur unless the center of the wafer is chipped, and in this case, post-processing to remove it is complicated. .

<Objective of the present invention> The present invention has been provided in view of the above-mentioned conventional problems.When cutting an ingot, in addition to the base portion of the ingot, the cutting side is held immovably in advance before the start of cutting. This prevents the cutting part from swinging and breaking in the final cutting area of the ingot, which prevents chipping from occurring, thereby eliminating the need for a slicing base and improving economical efficiency and quality. This is the purpose.

<Example> Hereinafter, preferred examples of the present invention will be described based on the drawings.

FIG. 1 is a schematic diagram of the present invention for cutting ingots into sections, in which an ingot W, which is a work material, is placed on a slidable work table 1 of an ingot cutting device main body via a spacer 2. The main body (base part) of the ingot is immovably fixed by a suitable clamper 3. Although the clamper shown in the figure is of a type that clamps and fixes the ingot W, other known means such as a type of clamper that grips or clamps one end of the ingot can be used. Reference numeral 4 designates an inner peripheral blade type blade which is stretched over a cylindrical spindle (not shown), and is a known blade having a cutting blade made of diamond abrasive grains or the like formed on the inner peripheral edge of a donut-shaped thin disk. The cylindrical spindle is known from slicing devices equipped with internal blades. Also, blade 4 in the example
1 schematically shows the upper half of the cross section, and since it is actually doughnut-shaped, the cross-sectional view is shown at appropriate intervals in Table 1.
Below the blade, there is a lower half of the blade, symmetrical to the upper half.

Reference numeral 10 denotes a vacuum holder device for gripping the cut end of the ingot according to the present invention, which is the cutting side.The main body 11 of the device has a cylindrical outer shape, and a relatively flexible lip 11 made of rubber or the like is attached to the periphery of the opening on the tip side.
a is integrally provided. The opening size of the main body 11 corresponds to the size of the portion of the ingot W to be gripped by suction, as will be described later.
When a tapered end of an ingot is to be gripped by suction as shown in the figure, the diameter of the ingot is formed to match that part. Further, reference numeral 11b is a vent hole that communicates with a vacuum pump (not shown) to reduce the pressure in the inner space of the holder device main body 11 when necessary. The vacuum holder device main body 11 is supported by its support base B and slides manually or automatically on the table 1, and the support base B can be fixed at any position by generally known means. .

Reference numeral 12 denotes a plurality of presser pins, which are appropriately disposed so as to be included in the holder device main body 11, and which are movable in the axial direction and can be used to cut the ingot when necessary.
Each pin contacts the WA and is individually adjusted to advance or retreat along the shape of the contact portion (grip portion). Furthermore, each pin can be fixed in its advanced and retracted positions, as will be described later.

Fig. 2 is a general view of the arrangement of the holding pins viewed from the front. They are arranged concentrically within the holder device main body, and are evenly scattered relative to the cut shape (circle) of the cut end WA that comes into contact with them. The layout is such that In the example shown, three wires are arranged on the virtual double circle line of the inner and outer circles with a phase angle of 60 degrees.

FIG. 3 shows a specific example of the configuration of the vacuum holder device 10. The holding pins 12 in the figure are based on the arrangement as shown in FIG. 2, and each pin on the virtual double circle line is shown.

Therefore, the holding pin 12 is always urged in the advancing direction to the left in the figure by the spring 12a wound around it, and is fixed at any forward or backward position by the locking ball 13 that protrudes and retracts in the axial direction when necessary. I'm trying to make it happen. Reference numeral 14 denotes a locking mechanism section that acts on the protrusion and retraction of the locking ball 13, and is connected to a feed shaft 15a (in the illustrated example, a screw connecting the motor A locking body 16 is provided with a locking element 16a corresponding to each of the locking balls 13. Therefore, the locking ball 13 and the locking mechanism part 14 constitute a locking device, and the locking ball is shaped like a pin, and the locking body 16 is shaped like a lever that acts directly on the holding pin 12 (for example, shaped like a crank). ) Various forms and configurations can be used as the locking device.

When cutting the ingot W with the above-described structure, the ingot W is first placed on the table 1, and the clamper 3 fixes the ingot base side immovably.

Next, slide the vacuum holder device 10 to cut the cut end of the ingot W.
The lip 11a of the holder device main body 11 is brought into contact with the end surface of the WA (in the illustrated example, it has a tapered shape). Lip 11
Since a is made of a flexible material, even if the abutment surface of the ingot has slight undulations and depressions, it can be brought into close contact with the ingot by following the unevenness.

Therefore, when the holder device main body 11 comes into contact with the cut end WA of the ingot, each of the holding pins 12 included in the device main body 11 presses the cut end WA.
It will retreat from the initial protruding state along the WA shape and will be positioned at the respective movement distance (Fig. 1,
Fig. 3 state).

After setting the contact as described above, first
1 is immovably fixed on the table 1 by a clamp mechanism (not shown). Next, the locking mechanism 14 is activated to immovably fix the presser pin 12 at that position by the locking ball 13. After that, if a vacuum pump (not shown) is operated to reduce the pressure inside the holder device main body 11 from the ventilation hole 11b, the pressure inside the main body, whose opening side is closed by the lip 11a, gradually becomes low and stabilizes at a predetermined pressure. do.

The holding pin 12 is only in contact with the cut end WA of the ingot, but since the holder device main body 11 is adsorbed, it cooperates with the holding pin 12 to grip and fix the end WA as if it were held. ie, the end is fixed immovably. Therefore, even if the table is then slid and cutting is started with the blade 4 at the corresponding position, the stress load generated at that time is transferred from the ingot base W to the table 1 side and from the cut end WA through the holder device 10. are transmitted and absorbed to the table 1 side, and even in the final cutting area, the cutting edge WA
etc. will not sway, and the situation of chipping as in the conventional case will not occur.

In the above embodiment, the cut end of the ingot has a tapered shape, but as is clear from its function and operation, the present invention is not limited to this, and can be used to cut an ingot with a concave-convex shape or a wafer slice. Needless to say, the end face can be used even if it has a flat surface shape or even if it has an inclined surface shape. FIG. 4 shows an example of wafer slicing.

That is, since the plurality of holding pins of the present invention can move forward and backward independently and lock at any position, the holding pins of the present invention can be adjusted according to the state of each part of the ingot end surface that the pins come into contact with. It can be locked at a position that follows the contact surface, and thereby the end surface can be evenly abutted and fixed. In this case, when the cut thickness is thin like a wafer slice, the vacuum holder device main body is attracted to the cut end face side, and when it is thicker, it is attracted to the outer periphery as in the above-mentioned embodiment.

<Effect> As explained in detail above, according to the present invention,
As the blade progresses in cutting the ingot, the cutting stress is transmitted and dispersed to the immovable ingot base and the holder device on the cutting side. In other words, the yield is improved. Furthermore, as described above, according to the present invention, it is possible to prevent the occurrence of chipping, so the slicing base, which was used only for preventing chipping, can be made unnecessary. In addition to reducing costs, the processes from attachment to removal after cutting and disposal are no longer necessary, and workability and productivity can be improved, resulting in significant effects on economy and quality. Furthermore, since the holder device of the present invention uses a presser pin, even if the pin abutment surface on the cutout side is uneven or sloped, it can be contacted evenly, and the vacuum holder device body can As long as it can be sucked, the shape of the gripping and fixing part can be used regardless of the shape. Furthermore, according to the present invention, the purpose can be achieved by attaching a vacuum holder device such as the present invention to a conventional configuration, and the practicality of the device can be achieved without a significant increase in cost. It is possible to provide an excellent and useful device.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a side view schematically showing the configuration of the present invention, FIG. The figure is a side sectional view showing a specific example of the configuration of the vacuum holder device, and FIG. 4 is a diagram illustrating another example of use of the device of the present invention. 1... table, 3... clamper, 4... blade, 10... vacuum holder device, 11...
Holder device main body, 11a... lip, 11b...
Ventilation hole, 12...Press pin, 13...Lock ball, 14...Lock mechanism section, 16...Lock operating body, W...Ingot.

Claims (1)

[Scope of Claims] 1. In an ingot cutting device that rotates a blade to cut an ingot whose proximal end is fixed, a plurality of ingots are arranged so as to be movable forward and backward facing the end face of the fixed ingot on the cutting surface side. A presser pin, a locking means for fixing each of the plurality of presser pins so that they cannot move forward or backward, and a reduced pressure suction means for vacuum suctioning the cutting side end face of the ingot toward the presser pin, An ingot cutting device characterized in that the ingot is suctioned and fixed to the end face of the ingot facing the pin.