Study On High-precision Temperature Acquisition Technology And Development Of Signal Acquisition Board

Precision machining,precision optics,semiconductor equipment and other fields place stringent requirements on the stability of the working environment temperature.Among them,the domestic lithography machine requires the temperature control accuracy of the working environment to reach ±0.005 °C,but there is no high-precision temperature measurement and control product that meets such demand in China.The development process of the lithography machine is extremely dependent on foreign temperature measurement equipment.Based on this,this thesis mainly studies the core technology of high precision temperature measurement and develops corresponding boards.The research of this thesis is mainly for semiconductor equipment-28 nm immersion lithography machine,for high-precision ambient temperature multi-point measurement of immersion lithography machine.High-precision temperature measurement technology combines various technologies such as sensor technology,analog measurement technology,signal Firstly,according to the overall demand,this paper establishes the modules needed to collect the board,studies the principle of various resistance thermometers,and designs the principle scheme of the temperature measurement module in detail.The error sources in high-precision temperature measurement process are studied: the stability of constant current source,the nonlinearity and conversion coefficient of A/D converter,thermoelectric potential,circuit offset,common mode interference,capacitive dielectric absorption,circuit noise,circuit error drift,etc.Analyze and study the characteristics and causes of the error source,and use special acquisition methods and special circuits to eliminate the error source.The special techniques used are: dual A/D synchronous sampling,A/D cross sampling,constant current source reversal,three Point test method,floating measurement technology.The hardware system framework is developed,and the design and component selection of each circuit unit are carried out.After calculation,the accuracy meets the requirements.Finally,a high-precision temperature acquisition board is designed and designed for system software.In the software,the digital filtering algorithm is used to further process the conversion result,eliminating the pulse interference and random interference during the measurement process.Finally,the high-precision temperature acquisition board is compared with the super resistance thermometer-1594 A.The acquisition accuracy is ±0.0002°C in the temperature range of 20°C-24°C,and it is put into the temperature control system of the lithography machine.The board runs reliably.