A method for detecting the quality of silicon substrate

Abstract

The invention provides a method for detecting quality of a silicon substrate. The method comprises the steps: firstly, the silicon substrate is heated and cooled; secondly, when the damaged layer of the back of the substrate has poor gettering effect or the supplied material of the silicon substrate is stained, dirt on the back and the edges of the silicon substrate or dirt in heating and cooling equipment overflows and transfers to the front side of the substrate; an epitaxial layer is developed on the silicon substrate, so that the integrity of the epitaxial growth lattices at the stained position of the silicon substrate is damaged, resulting in epitaxial growth defects; when the epitaxial layer on the silicon substrate is corroded, the epitaxial growth defects are exposed; the quality of the silicon substrate is judged by detecting the defects on the surface of the epitaxial layer by means of a metallographic microscope; the stained situation of the silicon substrate can be detected in advance without additionally arranging expensive detection equipment when the silicon substrate is supplied; therefore, the batch scrapping of the pipelining chips of sensitive devices is avoided and the delay of order delivery is prevented.

Description

technical field [0001] The invention relates to the technical field of semiconductor production, in particular to a method for inspecting the quality of a silicon substrate. Background technique [0002] In the single crystal preparation process of silicon substrate, grinding processes such as cylindrical rolling, positioning surface grinding, and slicing are an important source of metal impurity contamination, and sodium, magnesium, calcium, iron, etc. may be brought in during the grinding process. Metal ions, which will be hidden in the damaged layer and stained layer produced by grinding, will bring contamination sources to the subsequent process. If it cannot be effectively removed in a single or subsequent process, it will seriously affect the metal quality of the silicon substrate. [0003] The processing damage layer and contamination layer produced during the grinding process of the silicon substrate are generally initially removed by chemical etching. Silicon wafer...

AI Technical Summary

Problems solved by technology

Considering the cost and the difficulty of control, domestic suppliers generally use the sandblasting process to create damage on the back of the silicon wafer, which can bring about a stable back damage effect, but if the control is not good, it will cause metal contamination

There are also some suppliers who use the brushing process to create damage on the back of the silicon wafer, but it requires high process control. If the control is not good, it will often bring unstable back damage, resulting in subsequent epitaxy, oxidation, annealing and other processes. The damage on the back of the silicon wafer cannot effectively absorb the contamination on the front of the silicon wafer, which seriously affects the quality of the device

If the damage effect of the back damage layer itself is not enough to effectively remove impurities or defects on the silicon wafer, or to absorb too much contamination caused by substrate processing, it will bring hidden dangers to device processing. If it cannot be detected early, it will be Lead to batch scrap and order loss

[0005] At present, silicon substrate manufacturers generally use Total X-ray Fluorescence (TXRF) elemental analyzers to test metal ions (metal contamination) in silicon substrates, but it can only reach 1.0E 10 The accuracy of atoms / cm2, this is the case where the TXRF elemental analyzer shows that there is no metal ion exceeding the standard, but there is actually metal contamination.

Although for general products and processes, 1.0-5.0E 10 Metal contamination of atoms / cm2 has little effect, but for sensitive devices or processes, it will lead to problems such as epitaxial micro-defects, MOS short-channel leakage, Schott-level barrier pinholes, etc., seriously endangering the yield of devices and reliability

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