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

Abstract

The device for improving the detection accuracy of oxide layer thickness in the present invention includes a furnace tube, a crystal boat, several wafers and three control sheets placed on the top, middle and bottom of the crystal boat, and the wafers and control sheets are arranged and placed on the crystal boat. A blocking sheet is also placed above the control sheets located in the middle and bottom of the crystal boat. In addition, the present invention also provides a method for improving the detection accuracy of the thickness of the oxide layer, which includes loading several wafers and three control plates into the wafer boat, and placing a blocking plate respectively above the control plates at the middle and bottom of the wafer boat, and then Lift the crystal boat into the furnace tube for oxidation. In the present invention, the baffle arranged above the control plate can effectively prevent the thin film on the lower surface of the wafer from affecting the growth of the oxide layer of the control plate during the oxidation process, so that the thickness of the oxide layer on the three control plates is more stable, and can truly and accurately reflect the thickness of the entire furnace. The condition of the tube, which is conducive to more precise process control of the oxidation of the entire furnace tube.

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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