Calibration method of mass flow meter

A mass flowmeter and calibration method technology, applied in the field of flowmeter calibration, can solve the problems of inability to precisely control the refractive index of each layer, large measurement deviation, etc., and achieve the effect of restoring the refractive index to normal, ensuring efficiency, and ensuring anti-PID performance.

CN105203190BActive Publication Date: 2018-07-20TIANJIN YINGLI NEW ENERGY RESOURCES
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2018-07-20
Patent Text Reader

Abstract

The invention provides a calibration method for a mass flowmeter. The calibration method comprises the following steps: a) starting a main pump, and setting a mass flowmeter value of a gas A to be a flow nA under a standard process parameter when a butterfly valve is completely opened; b) after the gas is stabilized, recording a pressure intensity PA of a vacuum pressure gauge for measuring the gas A; c) turning off the mass flowmeter of the gas A, setting a mass flowmeter value of a gas B to be a flow nB under a standard process parameters by adopting the same method, and after the gas B is stabilized, recording a pressure intensity of a vacuum pressure gauge of the gas B to PB; d) recording a gas flow ratio Q=PA / PB; e) selecting a standard machine, measuring a pressure intensity ratio of the two gases of the standard machine to be a standard Q value on the standard machine, and recording as a Q standard; f) if the refraction rate of a certain machine generates a deviation, correcting the Q value thereof to a Q standard. By the adoption of the method, the defects that the measurement deviation of a PECVD (Plasma Enhanced Chemical Vapor Deposition) flowmeter is relatively large, and the refraction rate of each layer of the process cannot be accurately controlled in the prior art are overcome.
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Description

technical field

[0001] The invention relates to a calibration method of a flowmeter, in particular to a calibration method of a mass flowmeter, and more particularly to a calibration method of a tubular plasma enhanced chemical vapor deposition (PECVD) flowmeter. Background technique

[0002] In the production of crystalline silicon solar cells, anti-reflective film coating is an important step. At present, the most widely used method is to deposit silicon nitride film on a tubular plasma-enhanced chemical vapor deposition machine through silane and ammonia. Film thickness and refractive index are two important indicators to measure the performance of silicon nitride film, which are related to the efficiency and appearance of solar cells and the resistance to potential induced degradation (PID).

[0003] Currently, when depositing a silicon nitride film, the flow rates of silane and ammonia are controlled separately by two different mass flow meters, that is, the silane flow...

Examples

Embodiment Construction

[0024] Specific embodiments of the present invention will be described in detail below.

[0025] From the ideal gas state equation P*V=n*R*T (P is pressure, T is temperature, V is volume, n is the amount of gas substance, R is the ideal gas constant), it can be known that under the condition of constant temperature and volume , the pressure P is proportional to n.

[0026] In the tubular equipment, the calibration method of the tubular plasma enhanced chemical vapor deposition flowmeter according to the present invention can be used. First, close the furnace door, open the main pump, and set the silane mass flow meter to the flow rate n under the standard process parameters when the butterfly valve is fully opened. 硅烷 , after stabilization, record the pressure of the vacuum gauge as P 硅烷 . Then, close the silane flowmeter, and use the same method to set the ammonia flowmeter as the flow rate n under the standard process parameters 氨气 , record the corresponding pressure P o...