A device and method for improving detection precision of oxidated layer thickness

Abstract

This invention relates to a device for increasing accuracy of testing thickness of oxidation layer including a tube, a crystal boat, several wafers and three control sheets at the top, middle and the bottom of the boat, and the wafers and the control sheets are arrayed on the boat, two blocking sheets are set above the control sheets at the middle and bottom separately. This invention also provides a method including: putting several wafers and three control plates in the boat and putting blocking sheets above the control sheets at the middle and the bottom then putting the boat in the tube to be oxidized, in which, the blocking sheets above the control sheets can avoid that the film of the lower surface of the wafer will influence growth of the oxidation layer of the control sheet during oxidation.

Description

technical field [0001] The invention relates to a semiconductor manufacturing process, in particular to detection of the thickness of an oxide layer of a wafer. Background technique [0002] Since the wafer surface has a high affinity for oxygen molecules, it is easy to form an oxide layer when the wafer surface is exposed to an oxygen-containing atmosphere. At present, the commonly used method is to place the wafer in the furnace tube, then raise it to an appropriate temperature, and feed oxygen or water vapor and other oxygen-containing gases to grow a layer on the wafer, which has good adhesion to silicon materials and is insulating. The best silica. [0003] It is usually necessary to detect the thickness of the gate oxide layer to judge whether the process is up to standard. At present, the detection method for the thickness of the gate oxide layer in the furnace tube area is: place a control chip on the top, middle and bottom of the crystal boat, and measure the thic...

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Problems solved by technology

[0004] The disadvantage of this method is that when the wafer boat is full of wafers, the upper surface of the control wafers in the middle and lower parts of the furnace tube will face the back of the wafer. For some special process products, different films on the back of the wafer will face The thickness of the control sheet has different effects

For example, for a 0.18 micron process wafer, the back of the wafer is a layer of silicon nitride film (Si 3 N 4 ), because the silicon nitride film has a repelling effect on oxygen, so when the chip is placed on the top of the control chip, the growth rate of silicon dioxide on the control chip will slow down, and the thickness of the oxide layer on the control chip will also become thinner, resulting in measurement imprecise

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