Active gas flow control device for growing silicon epitaxy layer

Abstract

The invention discloses an active gas flow control device for the growth of an epitaxial layer of silicon. The device comprises a tee valve, a gas pipeline connected between the tee valve and a plurality of active gas mass flowmeters, a gas pipeline connected between the tee valve and an epitaxial layer growth chamber, and an exhaust bypass connected between the tee valve and a vacuum pump, wherein the exhaust bypass is provided with an automatic pressure control device which is controlled through a microprocessor; and according to the growth pressure of an epitaxial process, air pressure in the pipeline between the active gas mass flowmeter and the tee valve is regulated. The device can effectively control pressure from the active gas mass flowmeter to the tee valve, stabilize the growing speed of the initial stage of epitaxial growth and improve the thickness controllability of the epitaxial layer.

Description

technical field [0001] The invention relates to a gas flow control device used in the manufacturing process of semiconductor integrated circuits, in particular to an active gas flow control device used for growing silicon epitaxial layers. Background technique [0002] Silicon epitaxy is widely used in CMOS, BiCMOS and radio frequency integrated circuits, and the thickness of silicon epitaxial layer has a great influence on the performance of semiconductor devices. The thickness of the epitaxial layer is affected by the state of the epitaxial chamber and the supply of active gas, wherein the state of the epitaxial chamber can be stabilized by pretreatment of the epitaxial chamber. see figure 1 , when the active gas (SiHC 13 、PH 3 , B 2 h 6 、H 2 etc.) when being discharged from the exhaust bypass, the air pressure P1 in the pipeline between the three-way valve A and the active gas mass flow meter MFC must be greater than the air pressure P2 between the three-way valve A...

AI Technical Summary

Problems solved by technology

In general, when the active gas is switched from the exhaust bypass to the epitaxial growth chamber, the supply of the active gas will be unstable, resulting in an unstable growth rate at the beginning of growth, thus affecting the thickness of the overall epitaxial layer, especially when the thickness is less than 1 µm thin silicon epitaxial layers have a large control over the

[0003] The disadvantages of using a common pressure reducer to control the air pressure P1 are: 1. The air pressure P1 will be affected by the pumping speed capability; 2. Operation errors are prone to occur when the pressure reducer is manually adjusted; 3. No alarm can be given when the normal pressure reducer fails, etc.

[0004] In addition, because different epitaxial processes have different process pressures, it is difficult for ordinary pressure reducers to meet the requirements of different epitaxial processes for air pressure P1, and it is easy to misuse when operating the pressure reducer manually

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