Method for producing single crystal ingot and method for producing single crystal wafer

Abstract

Provided are: a method for producing a single crystal ingot with which it is possible to produce a single crystal ingot having excellent crystallinity at a good yield; and a method for producing a single crystal wafer with which it is possible to produce a wafer having excellent device characteristics. A method for producing a single crystal ingot according to the present invention comprises: a step for preparing a first single crystal ingot; a step in which the evaluation substrate (102) and the seed crystal ingot (103) are cut from the first single crystal ingot, and a projection surface (104) is formed on the seed crystal ingot; a step for measuring the local sound velocity of the evaluation substrate (102), and disposing a normal point (105) at a position on the evaluation substrate at which the measured value of the measured sound velocity is within a prescribed range; a step in which a map (107) of a normal point (105) is arranged on the projection surface; a step for cutting, from the seed crystal ingot, a crystal piece (109) that includes a straight line that passes through the map (107) of the normal point (105) and is parallel to the crystal growth axis; and a step for producing a second single crystal ingot using the crystal piece 109 as a seed crystal. A method for producing a single crystal wafer according to the present invention includes a step for slicing a second single crystal ingot produced by the method for producing a single crystal ingot to produce a single crystal wafer.

Description

technical field [0001] The present invention relates to a method for producing a single crystal ingot, and a method for producing a single crystal wafer for producing a single crystal wafer using the single crystal ingot produced by the method for producing a single crystal ingot. Background technique [0002] As a method of solidifying a melt to produce a single crystal, known are the pulling method, the Bridgman method, and the like. In these manufacturing methods, a crystal plate with uniform crystal alignment is used as a seed crystal, which is used as a starting material for crystal growth to increase the crystal size while maintaining the crystal alignment. A part of the large single crystal ingot produced in this way is cut out as a crystal piece, and this crystal piece is used as a starting material for the production of the next single crystal ingot as a seed crystal. [0003] Here, the quality of the grown single crystal ingot largely depends on the quality of the...

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Problems solved by technology

[0006] However, in the method of Patent Document 1, the internal defects that can be observed as etching marks in the crystal are limited to the specific orientation of the material.

For example, it cannot be applied to the case of pulling lithium tantalate (LT) or lithium niobate (LN) in the Y-axis direction of 30°~50°

[0007] In addition, in the method of Patent Document 2, it takes time to perform mirror polishing on all the cut-out seed crystals, and in order to visually recognize the stripe-like pattern, a skilled

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