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Wafer manufacturing method, quality evaluation method of reused slurry for wire saw and quality evaluation method of used slurry for wire saw

A manufacturing method and quality evaluation technology, applied in the field of wafer manufacturing, can solve problems such as increase in number, damage to slicing quality, and inability to sufficiently remove small particles, and achieve the effect of improving flatness and suppressing deterioration.

Pending Publication Date: 2020-05-26
SUMCO CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the present inventors have recognized that depending on the amount of small particles in the recovered used pulp, etc., there are cases where the small particles cannot be sufficiently removed, and in this case, the amount of small particles in the recycled pulp also increases, as As a result, slicing quality (i.e. wafer flatness) is compromised

Method used

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  • Wafer manufacturing method, quality evaluation method of reused slurry for wire saw and quality evaluation method of used slurry for wire saw
  • Wafer manufacturing method, quality evaluation method of reused slurry for wire saw and quality evaluation method of used slurry for wire saw
  • Wafer manufacturing method, quality evaluation method of reused slurry for wire saw and quality evaluation method of used slurry for wire saw

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Experimental program
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Effect test

Embodiment 1）

[0102] Small particle volume fraction R of recycled pulp used in slicing processing A In the case of 5.23% and 3.73%, the flatness of the wafer after slicing (As-sliced) was compared. exist Figure 43 shows the results of obtaining the thickness of one wafer cut out from the central portion of the ingot by the electrostatic capacity method at each level.

[0103] as from Figure 4 Obviously, using the small particle volume fraction R A The thickness of the wafer processed with the recycled slurry of 5.23% locally fluctuated in the center portion, and the flatness deteriorated. In contrast, using the small particle volume fraction R A The wafer processed with 3.73% recycled slurry had little local variation in thickness and good flatness.

Embodiment 2）

[0105] Using various small particle volume fractions R A The reused slurry was used to repeat the slicing process, and the flatness index of the obtained wafer, which is GBIR, was measured. GBIR is an index of overall flatness based on the back surface, and is defined as the deviation between the maximum thickness and the minimum thickness of the surface of the wafer relative to the reference plane when the back surface of the wafer is used as the reference plane. exist Figure 5 The volume fraction of small particles is shown in R A Relationship to the GBIR of the die. also, Figure 5 The respective plots are shown using an R A The average value of GBIR of all wafers obtained from 1 ingot for recycling slurry.

[0106] as from Figure 5 Obviously, by using the small particle volume fraction R A The recycled pulp is 5.0% or less, so that the GBIR can be reliably controlled to 10.0 μm or less.

Embodiment 3）

[0108] Small particle volume fraction R of used pulp after slicing B In the case of various values, the small particle volume fraction R of the prepared recycled slurry was measured A . In addition, as already described, when preparing the recycled slurry, the amounts of the abrasive grains and the coolant to be added were set so that the specific gravity of the recycled slurry was 1.570. exist Figure 6 The results are shown in .

[0109] as from Figure 6 Obviously, the small particle volume fraction R of the used pulp B When it is 10.0% or less, the small particle volume fraction of the recycled slurry can be reliably made 5.0% or less.

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Abstract

The invention relates to a wafer manufacturing method, a quality evaluation method of reuse slurry for a wire saw and a quality evaluation method of used slurry for a wire saw. Provided is a water manufacturing method capable of stably improving the flatness of a wafer by suppressing deterioration in processing quality due to the quality of reuse slurry provided for slicing with a wire saw. The ingot is sliced by using a wire saw supplied with slurry including abrasive grains and coolant. The used slurry is recovered, and after small particles are separated and removed, newly mixed abrasive and coolant are added to make a reuse slurry. The reuse slurry is supplied to the wire saw during the slicing of new ingots. The present invention is characterized in that the volume fraction of small particles RA of the reuse slurry according to the following definition is 5.0% or less. The volume fraction of small particles RA is the volume ratio occupied by the small particles among the particlesin the reuse slurry, wherein the average of the volume particle size distribution of the particles in the reuse slurry is set to RA1, and particles having a particle size equal to or less than the reference particle size RA2 equal to RA1 / 2, are defined as small particles.

Description

technical field [0001] The present invention relates to a wafer manufacturing method in which a process of obtaining a plurality of wafers by slicing an ingot with a wire saw supplied with slurry including abrasive grains and a coolant is repeated. Moreover, this invention relates to the quality evaluation method of the recycled pulp for wire saws, and the quality evaluation method of the used pulp for wire saws. Background technique [0002] Wafers to be substrates of semiconductor devices are produced by cutting an ingot made of silicon or compound semiconductors. In recent years, as an ingot cutting method, a free abrasive method in which a plurality of wafers are simultaneously obtained by slicing an ingot with a wire saw supplied with a slurry containing abrasive grains and a coolant has become mainstream. [0003] Here, the used slurry used in the slicing process is recovered, and the mixed abrasive grains and coolant are newly added after separating and removing smal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B28D5/04B28D7/00B24B27/06G06F30/20
CPCB28D5/045B28D5/0058B24B27/0633B24B27/0683
Inventor 利根俊辅铃木一彦南畑祐司舟山诚
Owner SUMCO CORP