JPH0286143A - Method of determining configurations of ingot end face - Google Patents

Abstract

PURPOSE:To make it possible to determine how the end face of an ingot from which a wafer has been cut off is corrected by a blade, by measuring degrees of warpage of the ingot in the cut direction and in the direction orthogonal thereto and determining configurations of the end face and degrees of warpage from predetermined reference data. CONSTITUTION:Three projections 4, 5 and 6 to be abutted on the end face 7 of an ingot are provided on the top face of a T-shaped measuring member 3 while a probe 8 of a displacement detector 8 is placed at the center between the projections 4 and 5. The probe 8 measures an amount of displacement in the orthogonal direction to the plane defined by the tips of the three projections 4, 5 and 6 and determines how the central part is warped in relation to the diametral direction. If values of X and Y are in an acceptable range, it is determined that the ingot has been cut in a desirable state. The configurations of the desirably cut end face of the ingot are classified into three basic groups and these data are previously stored in a computer for example. The measurement values are compared with the stored data and most approximate configurations corresponding thereto are displayed.

Description

[Detailed Description of the Invention] Fields of Application The present invention uses a device that cuts an ingot of silicon or the like into wafers when manufacturing semiconductor devices, and measures the state of warpage at approximately the center of the end face of the cut ingot.
The present invention relates to a method of determining the cutting status of a blade.

<Prior art> In order to cut a thin wafer into an accurate shape from the end of an ingot, it is necessary to pay attention to adjusting the tension of the rotating cutting blade and the dressing of the blade, but it is difficult to Determining the shape of a wafer three-dimensionally and rationally making adjustments based on this three-dimensional shape is a troublesome task. Conventionally, a displacement detector was applied to the end face of the ingot (the face after the wafer was cut off) to measure the shape. At this time, the detector was moved roughly in the diametrical direction and measurements were taken at several points to determine the approximate shape, but no consideration was given to what adjustments should be made from now on.

Summary of the Invention In FIG. 1, the ingot 1 held upright in the center hole of the rotating blade 2 is moved in the direction of the arrow (rightward in the figure) to cut off the wafer from the end of the ingot. Here, the moving direction of the ingot I is defined as the cutting direction.

In the present invention, first, the degree of warpage X of the end face of the ingot 1 is measured in the cutting direction, and then the degree of warp Y of the end face is measured in the direction perpendicular to the cutting direction. Then, by the combination of X and Y values (+)(-),
This method determines the basic shape of the end face and receives an instruction as to whether or not to perform blade adjustment processing based on this basic shape, allowing adjustments such as dressing and truing to be made rationally and easily.

<Example> A method for measuring the warp values X and Y of an end face in the present invention will be explained with reference to FIG.

3 that corresponds to the end surface 7 of the ingot on the upper surface of the T-shaped measuring member 3
The two protrusions 4, 5, . 6 will be provided. Here, 45 is the diameter direction, and 6 is the direction perpendicular to 4 and 5.

A contact 8 of the displacement detector 9 is provided at the center point between the protrusions 4 and 5. In addition, the displacement of the contactor 8 in the direction perpendicular to the surface formed by the tips of the three protrusions 4° 5.6 was measured, and how the center part was warped with respect to the diametrical direction 4.5 was measured. do. As mentioned above, the warpage value in the cutting direction is X, the warpage value in the 90' direction is Y, and the third
As shown in the figure, in the concave state indicated by the solid line, the warpage value X is (
+), and the swollen state is (-).

Although it is geometrically impossible to accurately determine the three-dimensional shape of the ingot end surface from only the X and Y values, the shape generated when cutting the ingot with the inner peripheral blade is The inventors have found that the probability of being able to make a determination based on the classification shown in FIG. 4 is extremely high.

Note that the term cylindrical here refers to the shape when the surface of the cylindrical body is cut out into a circular shape.

That is, in FIG. 4, when the left side view is set in the cutting direction (X direction) and the right side view is set in the orthogonal direction (Y direction), and the end face is measured in each, the flat surface shape obtained by proper cutting is
It can be classified into three basic shapes of displacement states: bowl shape (A), saddle shape (B), and cylindrical shape (C).

For example, if the warp value X when measured in the X direction is output as (+) and the warp value Y when measured in the Y direction is output as (+), the values shown in the rightmost column of the corresponding diagram in Fig. 4 are shown. Thus, the end face of the ingot is measured to have a so-called hemispherical bowl-shaped concave shape. Also, the warpage value X in the X direction is (+),
If the Y direction is output as (-), it is determined that the ingot end face has a saddle shape with a depression in the X direction.

Here, if the X and Y values are within the allowable range, it can be determined that the cutting situation is good. At this time, as shown in Figure 4, for the appropriate flat surface shape, the shape is determined to be one of three basic shapes, that is, a bowl shape (A), a saddle shape (B), or a cylindrical shape (C). It can also be displayed with diagrams. In other words, since the cut shape of the ingot end face can be classified into the above types, this is stored in advance using a computer, etc., and then the measured value and the stored data are compared and matched to find the closest correspondence. This makes it possible to output and display the shape using, for example, a CRT, plotter, or other hard copy device.

Furthermore, if the X and Y values exceed the allowable values, a warning can be displayed, and the X and Y values at that time and the set figure can also be displayed.

By determining the shape of the end face, it is possible to determine what adjustments need to be made to the blade. In other words, if the blade is bowl-shaped, the direction of blade dressing is determined by the shape of the concavities and convexities. Therefore, dressing is performed using this method.Furthermore, in the case of a cylindrical shape, the tension of the blade is adjusted to increase, and in the case of a saddle shape, truing work is performed, but the degree of correction is determined by the X and Y values. by.

Therefore, in addition to determining and displaying the basic shape, it is also possible to output a blade dressing signal and display correction items.

Note that by automating the measurement method, automatic measurement and automatic adjustment can also be made possible.

<Effects> According to the present invention, the basic shape of the end face can be determined by simple measurements in two directions, and based on this, the policy for the blade correction process can be determined.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the relationship between an ingot and a blade, Fig. 2 is an instrument for detecting warpage of an end face according to the present invention, Fig. 3 is an explanatory diagram showing a display of an end face, and Fig. 4 is an illustration of warpage value and basic end face shape. Relationship diagram. 1...Blade 2...Ingot 3...
T-shaped measuring member 4.5.6... Protrusion 8...
Contactor 9...Detector patent applicant Tokyo Seimitsu Co., Ltd. Figure 4 Cutting direction 0 ■ y (±)

Claims (2)

[Claims] (1) Measure the degree of warpage in the ingot diameter in the cutting direction and in the direction perpendicular to this for the end face of the ingot after cutting the wafer, and use this warp data to determine the shape of the end face based on standard data set in advance for a specific type. and a method for measuring the shape of an ingot end face to determine the degree of warpage. (2) The shape measuring method according to claim 1, wherein when the warp data indicates that the warp is equal to or greater than an allowable value, a processing signal for blade adjustment is transmitted and a determined shape is displayed.